Worldcat is a catalog of library catalogs -- huge!  Be sure to pay attention to various searching options.

Do you use Google Scholar? Make it more effective by linking it to the Library and gaining access to our subscriptions. 

Go to Google Scholar. Click on Settings, then Library Links in the left-hand column. Type in "Sonoma State University," check the box next to Sonoma State University, and save. Your search results will now include a Find It@SSU link. Click on Find It for full-text articles available from the SSU Library.