Are bibliographies/reference lists generally included in page/word counts?

I regularly assign my undergraduate students papers with a range of expected page/word length (e.g. 10-12 pages or 2500-3000 words). Is there any sort of rule as to whether or not to count a works cited page(s0 (and its equivalent in the other citation styles) in determining if a paper meets this limit? I've discussed this with colleagues and heard varying answers.