Theses and dissertations are great resources. Though often unpublished, these have been researched and written with the same rigor as published sources. They also contain extensive bibliographies that you can use to find more materials.
Index to doctoral dissertations from 1637 to the present, with abstracts since 1980. A number of master's theses are also indexed, with abstracts since 1988. Many are available for download in pdf format. UCLA has access to all full text dissertations in the database. Non-UCLA users may use Dissertations Express to purchase digital or print copies of individual dissertations.
Over 5 million dissertations and theses available in OCLC member libraries. Many theses are available electronically, at no charge, directly from the publishing institution. UCLA students, faculty, and staff can request non-UCLA dissertations via interlibrary loan.