They were purses made out of shells of classic books. I saw a few Shakespeare ones. It's not a huge or intellectual reference to Shakespeare, I just thought it was a funny way to use the books.
Also, another small Shakespeare reference I've found was in my Italian book. I am taking first semester Italian, and in the first chapter of the book, in the section about the verb "essere," which means, "to be," there is a picture of a teacher pointing at a blackboard that says "essere, non essere," or, "To be or not to be." Just a small funny reference to Hamlet I wanted to share.