do not refer to forthcoming work
Cite “forthcoming work” only if there is a publicly available preprint. (The reason is that sometimes the work ends up not appearing for years or does not appear at all, and the announcement serves to discourage others from working on the problem, which can be damaging to the field: see the third bullet in Section I of the AMS Policy Statement on Ethical Guidelines ( http://www.ams.org/about-us/governance/policy-statements/sec-ethics).
Tags: writing.