After searching books, you will want to look for scholarly articles. There are differences between the two types of materials. Books will deal in depth with a topic or artist, where articles are much more narrow in focus. Also, because of their publication strategies, there are a LOT more articles to wade through in a result set than a book search. Just saying!
CSUSM offers you several ways to get to articles.
Art Full Text (the name says it all, but there will be a mix of scholarly and popular materials)
JSTOR (scholarly, full text general database)
Project Muse (scholarly, full text, general database)
ProQuest - Arts (much of this is popular press, rather than scholarly, but still has useful content)
Here is an example of a search in Art Full Text database:
Tip: There are a lot of ways to do searches, this is a basic set of steps. See your librarian for more.