Databases are also fantastic places to search for primary sources. If you only have time to look at a few, take a look below at some of our recommended databases that focus on U.S. History primary source materials from the 20th century. See the "Full List of Databases" tabs to find other useful databases covering 20th century U.S. History. Many of these databases include eras beyond the 20th century.
Unlimited users.
Presents thematic content focusing on the evolution of Hispanic civil rights, religious thought, and the growing presence of women writers from the late 19th and 20th centuries. Rare and relevant books and newspapers – including rare anarchist newspapers – are presented in their original form. Extensive manuscript collections of both organizations and individuals are included for viewing, and are indexed for ease of search and maximum discovery. This collection offers a unique approach by focusing exclusively on the Latino-Hispanic history of the United States.
Unlimited users.
Includes the full image of articles published in the Chicago Defender from 1910 to 2010. You can browse individual issues by clicking Publications at the top of the screen, or search by keyword(s), author(s), article title, date ranges, and more. Includes illustrations and advertisements. The Chicago Defender was the most influential African-American newspaper of the 20th century. With the majority of its readership outside the Chicago region, it served as the de facto national black newspaper in the U.S. The Defender covered events in the South, such as lynchings, that Southern black newspapers could not safely report. The paper was a major influence for the Great Migration of African Americans to the North in the early 20th century. Later issues of the Chicago Defender are in the Ethnic NewsWatch database.
Unlimited users.
Artemis Primary Sources is an integrated research environment that allows users to search across Gale primary source collections. Artemis Primary Sources takes users beyond a simple search and retrieve workflow, allowing them to analyze content using frequency and term-relationship tools. Currently, Artemis Primary Sources includes Eighteenth Century Collections Online and Nineteenth Century Collections Online. Other resources are being added.
Unlimited users.
This resource’s unique content is primarily composed of video oral histories recording the African American experience in the first-person. Testimonies captured in The HistoryMakers Collection interviews are conducted in homes and offices across the United States and abroad. The interviews reveal the broad scope of narratives of African American men and women who have made significant contributions to American life, history, and culture during the 19th, 20th, and 21st centuries.
Unlimited users.
Independent Voices is an open access digital collection of alternative press newspapers, magazines and journals, drawn from the special collections of participating libraries. These periodicals were produced by feminists, dissident GIs, campus radicals, Native Americans, anti-war activists, Black Power advocates, Hispanics, LGBT activists, the extreme right-wing press and alternative literary magazines during the latter half of the 20th century.
Unlimited users.
Contains over 1,500 hours of footage of the full surviving broadcast run of network television's longest running program. Thousands of interviews, panels, and debates are available online in one cross-searchable interface.
Unlimited users.
Updated annually. Includes all the articles published since the first issue of the paper in 1851. Provides full text and full image articles with digital reproductions of every page, every article and every issue in PDF format. In addition to news stories, includes editorials, letters to the editor, obituaries, birth and marriage announcements, photos, and advertisements.
More recent years are also available in other full text resources.
Unlimited users.
Documents the key events, trends, and movements in 1960s America. Through letters, diaries, memoirs, oral histories; accounts from official, radical, and alternative organizations; posters, broadsides, pamphlets, advertisements, and rare materials, the collection tells the story of the 60s. Themes include: civil rights, counter-culture, mass and underground media, sexual revolution, student activism, the Vietnam War, and women's rights.
Unlimited users.
Digitized copies and content of Texas newspapers, including The Austin Daily Texan (1900-2019), Galveston Daily News (1865-2017), San Antonio Express (1865-1977), San Antonio Light (1883-1977)and hundreds of other Texas newspapers.
Unlimited users.
Primary source documents on the Vietnam War and American Foreign Policy from 1960-1975. Collections on the Vietnam War cover U.S. involvement in the region from the early days of the Kennedy administration, through the escalation of the war during the Johnson administration, to the final resolution of the war at the Paris Peace Talks and the evacuation of U.S. troops in 1973. Along the way, documents in this module trace the actions and decisions at the highest levels of the U.S. foreign policy apparatus, as well as events on the ground in Vietnam, from the perspective of State Department officials, Associated Press reporters, and members of the U.S. Armed forces, including the Marines and the Military Assistance Command Vietnam.
Unlimited users.
The African American Historical Serials Collection, developed in conjunction with American Theological Library Association (ATLA) features more than 170 unique periodical titles related to the history of African American life and culture, with extensive coverage of religious organizations, churches, and institutions. Material was published between 1829 and 1922.
Unlimited users.
Updated regularly. A comprehensive collection of scholarship focused on the lives and events which have shaped African American and African history and culture, coupled with sophisticated technology permitting precise search and browse capabilities. Features over 7,500 articles from Oxford's authoritative reference works, approximately 100 primary sources with specially written commentaries, over 1,000 images, over 100 maps, over 200 charts and tables, timelines to guide researchers through the history of African Americans and over 6,000 biographies.
Unlimited users.
Updated regularly. Includes more than 1,000 U.S. historical newspapers published between 1690 and the 1990s, including titles from all 50 states. Search by dates/eras, article types (news & opinion, election returns, letters, poetry/songs, legislative, prices, advertisements, matrimony & death notices), region/state, and newspaper name.
Unlimited users.
Updated regularly. This collection allows students and researchers to analyze historical events, and their presentation over time, through documentaries, commercial and governmental newsreels and archival and public affairs footage. The full runs of newsreels from United Newsreel and Universal Newsreel from 1929 through 1967 are included. On 14th September 2012, American History in Video was updated. As of this update there are 6,002 videos (including 3,211 documentaries) equaling 1,616 hours in American History in Video.
Unlimited users.
Updated daily. Contains periodicals published between 1740 and 1940, including special interest and general magazines, literary and professional journals, children's and women's magazines and many other historically-significant periodicals.
Unlimited users.
Provides access to a digital collection of historical content pertaining to U.S. Hispanic history, literature and culture. Includes historical articles, newspapers, religious pamphlets, broadsides, historical books, letters, short stories, poems, advertisements, and more. The content is in Spanish (80%) and English (20%), and is searchable in both languages. Materials are drawn from the Recovering the U.S. Hispanic Literary Heritage Project.
Unlimited users.
Presents thematic content focusing on the evolution of Hispanic civil rights, religious thought, and the growing presence of women writers from the late 19th and 20th centuries. Rare and relevant books and newspapers – including rare anarchist newspapers – are presented in their original form. Extensive manuscript collections of both organizations and individuals are included for viewing, and are indexed for ease of search and maximum discovery. This collection offers a unique approach by focusing exclusively on the Latino-Hispanic history of the United States.
Unlimited users.
Documents the Asian American experience as dramatized in works by writers from the 18th century to the present. Brings together biographies, a performance database, production details, and associated visual resources, including photos, playbills, and manuscript images. Brings together more than 250 plays, beginning with the works of Sadakichi Hartmann in the late nineteenth century and progresses to the writings of contemporary playwrights, such as Philip Kan Gotanda, Elizabeth Wong, and Jeannie Barroga. Along with many works by writers of Japanese, Filipino, Vietnamese, and Chinese descent, includes plays by writers of Hawaiian, Indian, Thai, Korean, Persian, and Malaysian ancestry.
Unlimited users.
Full page and article images of Atlanta Daily World (1931-2010) and Atlanta World (1931-1932), with searchable full text. Users can study the progression of issues over time by browsing issues of this historic Southern Black community newspaper, including news articles, photos, advertisements, classified ads, obituaries, editorials, cartoons, and more.
Unlimited users.
Searchable database of the "Afro-American", one of the most widely circulated African-American newspapers on the Atlantic Coast. Includes full-text and full-image newspaper articles published from 1893 to 2010. Digital reproductions of every page and every article from every issue are available in downloadable PDF files.
Unlimited users.
Updated regularly. Contains approximately 1200 plays written from the mid-1800s to the present, together with detailed, fielded information on related productions, theaters, production companies, and more. Also includes selected playbills, production photographs and other ephemera related to the plays. The content represents North America, English-speaking Africa, the Caribbean, and other African diaspora countries. Many of the works are rare, hard-to-find, or out of print.
Unlimited users.
Updated daily. Provides an index to print and electronic publications created by Federal agencies. When available, links are provided to the full text of these publications.
Unlimited users.
Includes the full image of articles published in the Chicago Defender from 1910 to 2010. You can browse individual issues by clicking Publications at the top of the screen, or search by keyword(s), author(s), article title, date ranges, and more. Includes illustrations and advertisements. The Chicago Defender was the most influential African-American newspaper of the 20th century. With the majority of its readership outside the Chicago region, it served as the de facto national black newspaper in the U.S. The Defender covered events in the South, such as lynchings, that Southern black newspapers could not safely report. The paper was a major influence for the Great Migration of African Americans to the North in the early 20th century. Later issues of the Chicago Defender are in the Ethnic NewsWatch database.
Unlimited users.
Updated annually. Offers reporting on the major activities of the U.S. Congress, including detailed information on political issues during each congressional session back to 1945. Includes roll call votes, interest group ratings, data on presidential support, party unity and voting participation records for members of Congress and texts of presidential messages. The Policy Tracker feature allows you to trace major policy issues across several years to see how it has developed over time.
Unlimited users.
Contains detailed descriptive, statistical and analytical information on United States federal and gubernatorial elections, focusing on campaigns, political parties, and voter demographics. Data export tools allow for customized data downloads for easy statistical analysis.
Unlimited users.
The National Security Archive is an independent non-governmental research institute and library located at The George Washington University.Updated annually. The Digital National Security Archive includes 53 collections of declassified documents, consisting of over 94,000 indexed documents, with more than 733,000 total pages. Each of these collections, compiled by top scholars and experts, exhaustively covers the most critical world events, countries, and U.S. policy decisions from post World War II through the 21st century. Glossaries, chronologies, bibliographies, overviews, and photographs are included.
The National Security Archive is an independent non-governmental research institute and library located at The George Washington University.
Unlimited users.
A collection of large-scale, detailed maps from 1867-1970 depicting the commercial, industrial, and residential sections of more than 12,000 U.S. towns and cities.
The available states on our site are: Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, Texas, and Virginia.
Access to this resource is funded by the Littlefield Fund for Southern History.
2 users.
Detailed indexing of over 800 periodicals, many of them peer-reviewed. Indexing from 33 historic print index cumulations. Citations for 850,000 articles, including book reviews. Updated subject headings to make finding older citations easier, though original subject headings are also retained to provide insight into the way issues of the day were framed.
Unlimited users.
Presents over 9,000 images, with database information, relating to the early history of advertising in the United States. The materials, drawn from the Rare Book, Manuscript, and Special Collections Library at Duke University, provide a significant perspective on the early evolution of this most ubiquitous feature of modern American business and culture.
Unlimited users.
Provides full text access to primary source documents from the British Empire (the Empire encompassed Africa, the Americas, Australia, Oceania, and South Asia). Documents include travel accounts, the literature of Empire, photography and illustration, religious material, and records on issues of race and class in the colonial context.
Search across Adam Matthew primary source databases using AM Explorer
Unlimited users.
An archival research resource containing the essential primary sources for studying the history of the film and entertainment industries, from the era of vaudeville and silent movies through to 2000. The core US and UK trade magazines covering film, music, broadcasting and theater are all included, together with film fan magazines and music press titles. Magazines have been scanned cover-to-cover in high-resolution color, with granular indexing of all articles, covers, ads and reviews.
Unlimited users.
Digitized historical documents from the records of voting rights activist and civil rights leader, Fannie Lou Hamer. Her papers contain more than three thousand pieces of correspondence plus financial records, programs, photographs, newspaper articles, invitations, and other printed items.
Unlimited users.
This online collection brings together documents from 16 archives and libraries from around the world and the geographical spread of material allows scholars to take either a comparative approach or focus on a particular region. The collection deals with some of the major themes of frontier existence including: Settlement development, law and order, violence, expeditions and exploration, relations with indigenous peoples, trade and commerce, death and disease, missionaries and religion, women’s history, military matters, mining, gold rushes, settler governance, contested boundaries, agriculture and livestock.
Search across Adam Matthew primary source databases using AM Explorer
Unlimited users.
A full text collection of books, pamphlets and periodicals reflecting the evolution of a feminist consciousness and the movement for women's rights. Includes publications from Europe, the U.S., the United Kingdom, Canada, and New Zealand. The ASCII text is searchable by keyword and Boolean operators, and records are linked to the corresponding page images, viewable with the Acrobat Reader plugin from Adobe.
Unlimited users.
Updated annually. Citations to articles, essays and book reviews relating to Latin America or from Latin American periodicals. Primarily Spanish, English and Portuguese titles.
Unlimited users.
Provides full text and page impages of Harper's Weekly, one of the most important serials of nineteenth-century America. Includes browse issues by date, search the index, search for the full text of articles, browse literature by genre, or find people by their cccupation or role in society.
The University of Texas Libraries subscribes to the entire database, including The Civil War Era (1857-1865), Reconstruction I (1866-1871), Reconstruction II (1872-1877), Gilded Age I (1878-1883), Gilded Age II (1884-1889), Gilded Age III (1890-1895), Gilded Age IV (1896-1901), Gilded Age V (1902-1907), and Gilded Age VI (1908-1912).
Unlimited users.
Provides access to a large compilation of Spanish-language newspapers printed in the U.S. during the 19th and 20th centuries. Includes many newspapers published bilingually in Spanish and English. Features hundreds of Hispanic American newspapers, including many long scattered and forgotten titles published in the 19th century.
Based on the “Recovering the U.S. Hispanic Literary Heritage Project", a national research effort directed by Professor Nicolás Kanellos.
Unlimited users.
Provides access to historical Jewish newspapers published around the world from the nineteenth century onwards. Includes digital versions of each newspaper, making it possible to view the papers in their original layout. Full-text search is also available for all content published over the course of each newspaper’s publication.
Unlimited users.
Updated regularly. Provides a standard source for the quantitative facts of American history. Expands and revises information provided in Historical Statistics of the United States, previously produced by the U.S. Bureau of the Census, and includes thirty years of new data and scholarship. Footnotes and explanatory information provide instructional information about the data and sources of the data.
Permits users to graph individual tables and create customized tables and spreadsheets reflecting particular areas of interest. Data is downloadable in Excel or CSV; also download entire groups of tables as a zip file.
Unlimited users.
This resource’s unique content is primarily composed of video oral histories recording the African American experience in the first-person. Testimonies captured in The HistoryMakers Collection interviews are conducted in homes and offices across the United States and abroad. The interviews reveal the broad scope of narratives of African American men and women who have made significant contributions to American life, history, and culture during the 19th, 20th, and 21st centuries.
Unlimited users.
LGBT Thought and Culture is an online primary source database hosting the key works and archival documentation of LGBT political and social movements throughout the 20th century and into the present day. The collection contains seminal texts, letters, periodicals, speeches, interviews, and ephemera.
The resource provides a look into LGBT life from the late 19th to the early 21st centuries, covering topics such as bars and saloons, gay communities, clubs and social organizations, gay activism and activists, gay rights, AIDS, films, politics, books, medical treatments and procedures, gender identity, discrimination, and more.
Includes material from the Kinsey Institute Archive and Library, the ONE National Gay & Lesbian Archives, the Jeanne Cordova Papers, the Magnus Hirschfeld Collection, and more.
Unlimited users.
Searchable digital archive of Life Magazine covering national and international events, documentaries, popular culture, and business from November 1936 through December 2000.
Unlimited users.
Designed to complement The Making of Modern Law: Legal Treatises, this archive offers online access to state and municipal codes, documents relating to constitutional conventions, and other resources in American legal history. The term “primary sources” is used not in the historian’s sense of a manuscript, letter or diary, but rather in the legal sense of a case, statute or regulation.
Access to this resource is funded by the Tarlton Law Library at the Jamail Center for Legal Research.
Unlimited users.
Comprises over 10,000 titles and more than 2 million pages of fully searchable content, covering trial books from all countries and languages (although the great majority are in English and published in the U.S. or Great Britain); includes books covering multiple trials as well as books about a single trial. Based on the law libraries of Harvard and Yale, and of the Association of the Bar of the City of New York, as well as some from the British Library. The category of "trials" includes unofficially published accounts of trials; official trial documents, briefs, and arguments where these were printed as separate publications; official, separately published records of legislative proceedings; administrative proceedings; and arbitrations (domestic and international).
Access to this resource is funded by the Tarlton Law Library at the Jamail Center for Legal Research.
Unlimited users.
Newspaper Source Plus provides a full-text digital collection of the world's major news content. It includes millions of articles from newspapers, newswires and news magazines. In addition, it offers television and radio transcripts and ongoing daily updates from popular news sources.
Unlimited users.
Full page and article images of various editions of the New York Amsterdam News newspaper, with combined coverage from 1922 to 2010. The newspaper offers primary source material relevant to the study of American history and African-American culture, history, politics, and the arts. Coverage includes news stories, editorials, letters to the editor, obituaries, birth and marriage announcements, photos, and advertisements. Later issues of the New York Amsterdam News are in the Ethnic NewsWatch database.
Unlimited users.
Updated annually. Includes all the articles published since the first issue of the paper in 1851. Provides full text and full image articles with digital reproductions of every page, every article and every issue in PDF format. In addition to news stories, includes editorials, letters to the editor, obituaries, birth and marriage announcements, photos, and advertisements.
More recent years are also available in other full text resources.
Unlimited users.
An archive of Newsweek magazine, one of the premier US weeklies of the 20th -21st centuries. With coverage from 1933 through 2012, it comprises 80 years of news reporting and commentary, charting the key US and global events during this period. Its diverse content beyond news and politics (in areas including business, science/technology, arts, travel, and family life) is such that there is valuable material for researchers in many fields, from history and political science through to economics, women's studies, and media history.
Unlimited users.
Updated quarterly (until completed). Provides a view of what it meant to immigrate to America and Canada between 1800 and 1950. When completed, will include more than 100,000 pages of personal narratives including letters, diaries, pamphlets, autobiographies, and oral histories. Currently contains 342 authors and approximately 37,500 pages of information.
Unlimited users.
A collection of biographical material of American Indians and Canadian First Peoples in their own words and through the words of others. Includes biographies, autobiographies, personal narratives, speeches, diaries, letters, oral histories, reference works, manuscripts, photographs and audio files.Sources include rare books and biographies from more than 100 Indian publications, such as The Arrow, the Cherokee Phoenix, and the Chickasaw Intelligencer. The collection includes 2,000 oral histories presented in audio and transcript form and at least 20,000 photographs from the Bureau of Indian Affairs, Edward Curtis, and many rare collections.
4 users.
Updated monthly. A comprehensive compilation of public opinion surveys, containing the full text of more than 350,000 questions and responses from 14,000 surveys conducted by 700 polling organizations in the United States and more than 80 other countries.
Unlimited users.
Updated daily. Provides indexing of many Congressional publications, including Bills, Resolutions, Hearings, Committee Prints, Reports, Documents and Congressional Research Service Reports.
House and Senate Reports and Documents indexed in ProQuest Congressional (1817-1969) are available in full text in the Serial Set database. Our subscription to ProQuest Congressional does not include full text of the Serial Set.
Congressional Hearings after 2013 and House and Senate Documents and Reports indexed in ProQuest Congressional (1995 to present) are available in full text on Govinfo.gov site from the Government Printing Office.
Unlimited users.
The collection consists of records of the United Domestic Workers Union (U.S) from 1965-1979. The National Domestic Workers Union was founded in Atlanta in 1968 by Dorothy Bolden to help women engaged in household work. Correspondence (1965-1979) reflects Bolden's efforts in organizing the Union and includes such correspondence with Georgia and national political figures. In addition, the collection contains minutes of the Union, financial documents and files relating to Equal Opportunity Atlanta.
Unlimited users.
Documenting three pivotal decades in the fight for civil rights, this resource showcases the speeches, reports, surveys and analyses produced by the Fisk University Race Relations Department which with its annual Institute were set up by the American Missionary Association to investigate problem areas in race relations and develop methods for educating communities and preventing conflict. Department’s staff and Institute participants, including Charles S. Johnson, Dr Martin Luther King, Jr., and Thurgood Marshall.
Search across Adam Matthew primary source databases using AM Explorer
4 users.
Contains comprehensive indexing of the most popular general-interest periodicals published in the United States and reflects the history of 20th century America. Covers more than 375 titles.
5 users.
Updated semi-annually. The Retrospective Index to Music Periodicals (RIPM: Repertoire International de la Presse Musicale) indexes articles from over 60 international 19th and 20th-century music periodicals in all major languages. Citations include author and title of article, periodical data, and a brief note of contents (e.g., "review"). Annotations or abstracts are not included. Includes writings about composers, performers, and compositions, and provides a documentary history of 19th-century music and musical life.
Unlimited users.
Provided by the Roper Center for Public Opinion Research at Cornell University, Roper iPoll is the largest collection of public opinion poll data with results from 1935 to the present. Roper iPoll contains nearly 800,000 questions and over 23,000 datasets from both U.S. and international polling firms. Surveys cover any number of topics including, social issues, politics, pop culture, international affairs, science, the environment, and much more. When available, results charts, demographic crosstabs and full datasets are provided for immediate download.
Unlimited users.
Provides over 14,000 primary source titles based on Joseph Sabin's bibliography, Bibliotheca Americana. Materials describe every aspect of life in the Western Hemisphere from 1500 to the 1890s. Included are books, pamphlets, serials and other documents that provide original accounts of exploration, trade, colonialism, slavery and abolition, the western movement, Native Americans, military actions and much more. Searchable in a variety of ways, including: author, title, year of publication, and subject.
Unlimited users.
Provides a portal for slavery studies, bringing together documents and collections covering an extensive time period spanning six centuries, from libraries and archives across the Atlantic world. Offers images of many thousands of original manuscripts, pamphlets, books, paintings, maps and images not available elsewhere, links to other online sources approved by scholars and a series of contextual essays by leading authorities from around the world.
Includes extensive coverage of topics such as the African Coast; the Middle Passage; the varieties of slave experience (urban, domestic, industrial, farm, ranch and plantation); Spiritualism and Religion; Resistance and Revolts; the Underground Railroad; the Abolition Movement; Legislation; Education; the Legacy of Slavery and Slavery Today.
Search across Adam Matthew primary source databases using AM Explorer
Unlimited users.
Updated regularly. Provides easy access to historical census data for the United States. Allows users to visually analyze and understand the demography of any part of the United States with access to the following:
Users can examine geographic areas while selecting the type of data to be shown, such as population density or income level. The corresponding data tables are also available.
Unlimited users.
The Time Magazine Archive presents an extensive collection of the prominent weekly news reports of national and international current events, politics, sports, and entertainment dating back to its first issue in March 1923 through December 2000, presented in a comprehensive cover-to-cover format.
Unlimited users.
Updated regularly. Provides a digital reproduction of the United States Congressional Serial Set, consisting of the Reports, Documents, and Journals of the U.S. Senate and House of Representatives. Content covers years 1817 to 1980.
The maps published as part of the U. S. Congressional Serial Set publications are also searchable. Includes all maps from 1817 - 1980.
Unlimited users.
Provides nearly 11 million pages of records and briefs from over 150,000 cases brought before the U.S. Supreme Court in the period 1832-1978. Also contains full-text search capabilities to more than 350,000 documents, including appellant's and appellee's briefs, oral transcripts, and petitions for writ of certiorari.
Access to this resource is funded by the Tarlton Law Library at the Jamail Center for Legal Research.
Unlimited users.
Includes both Volumes 1 and 2.
Unlimited users.
Updated daily. Provides a searchable archive of abstracts of news broadcasts from 1968 to present (ABC, CBS, NBC), 1995 to present (CNN), and selected content from PBS and FOX News. Also includes more than 9,000 hours of special news-related programming including ABC's Nightline since 1989. These special reports and periodic news broadcasts cover presidential press conferences and political campaign coverage, and national and international events such as the Watergate hearings, the plight of American hostages in Iran, the Persian Gulf war, and the terrorist attack on the United States on September 11, 2001
See Additional Info section for information on requesting loans from the collection.
Unlimited users.
The Vogue Archive contains the entire run of Vogue magazine (US edition), from the first issue in 1892 to the current month, reproduced in high-resolution color page images. Every page, advertisement, cover and fold-out has been included, with rich indexing enabling you to find images by garment type, designer and brand names. The Vogue Archive preserves the work of the world's greatest fashion designers, stylists and photographers and is a unique record of American and international fashion, culture and society from the dawn of the modern era to the present day.
Unlimited users.
Updated quarterly. Organized around the history of women in social movements in the U.S. between 1600 and 2000. A resource for the teaching the history of women in the United States. Consists of 74 editorial projects with more than 2200 primary documents intended for use in high school and college history classrooms. Also includes a major collection of links to related websites and a search engine that permits users to do full text searching of all the primary documents mounted on the site.
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 Generic License.