What do you call literature that a student may choose to study for a certain course. I don't mean optional literature, or reference material, but rather a selection of books, articles etc from which the student **must** choose a given number of texts, but they still get to choose **within** that selection. Do you say that it is *elective*? *Electable*? What? And, while I'm at it, which is the better choice of *course literature* and *course reading* for the books etc that you need to study for a course at the university? (Or should it be something else entirely?)

Thank you!