The Online Writing Lab at Purdue ( owl.english.purdue.edu/owl/resource/717/01/ ) should probably be your for any questions regarding citation (for you and for your students). That said, if you're a proponent of handouts, here are three god Chicago-style citation guides that you could give to your students. The first is from the University of Washington, the second from Texas A&M, and the third from the University of Texas. Washington's might be the best, visually speaking, but all are solid in terms of content. Try them out and see which one you like!