The Online Archive of California (OAC) is a searchable database that includes finding aids for archival and primary source collections at more than 200 libraries, special collections, archives, historical societies, and museums in California, including Special Collections & Archives at CSUN.
After searching, you can limit your search results by holding institution, so you can see everything on your topic at other repositories in Los Angeles (UCLA, Occidental, Loyola Marymount, etc.) that have contributed finding aids to the OAC.