Providers
- Delft University of Technology (226)
- Diener Education Fund (26)
- Digital Learn (93)
- Digital Public Library of America (139)
- Light and Matter (14)
- Linn-Benton Community College (95)
- Look At Physics (38)
- Lumen Learning (67)
- Lyryx Learning (11)
- Maricopa Open Digital Press (12)
- Markkula Center for Applied Ethics at Santa Clara University (29)
- Mathematics Assessment Project (11)
- Milne Publishing (11)
- Minnesota Libraries Publishing Project (11)
- NASA (11)
- National Endowment for the Arts (11)
- National Oceanic and Atmospheric Administration (84)
- New Prairie Press (20)
- New York University (22)
- Niagara College (26)
- NSCC Libraries Pressbooks (19)
- TeachEngineering (649)
- The Center for Computer Assisted Legal Instruction (CALI) (43)
- The Open Anthology of Literature in English (17)
- University of Copenhagen (145)
- University of Michigan (40)
- University of Minnesota (32)
- University of Minnesota Libraries Publishing (12)
- University of Oxford (105)
- University of Saskatchewan (14)
- University of Texas at Austin (46)
- University of Washington Libraries (12)
- University of Wisconsin (18)
- University System of Georgia (57)