George Mason University has launched the Mason OER Metafinder, designed by GMU Librarian Wally Grotophorst, Associate University Librarian for Digital Programs and Systems. It searches a broad range of Open Educational Resource Collections, such as as the Digital Public Library, the Library of Congress American Memory Collection, MERLOT, and College Open Textbooks. Read more about the Metafinder at Deep Web Tech Blog, or try it out below.
Many sources have more than one type of document, just as a print journal may also publish conference papers or technical papers. Be sure to check in other categories, especially the General/Mixed Media category.