OneSearch - If the Pfau Library has it, it will be in the CSUSB area of OneSearch. If not, use the all-CSU portion of OneSearch and request it using CSU+. For items not held by any of the CSU campuses, you will need to order it through interlibrary loan (ILL).
You could also search the Library of Congress, Worldcat, OhioLink, or Amazon if you are looking for more titles suitable to your topic.
Below are listed the most productive databases for research in your field.