How do I reference a conference paper that is due to be published later this year I am writing a paper that builds on a previous work. The previous work has been accepted at a conference and will be published as part of the proceedings, but it hasn't been published yet. Do I just reference it using the standard format for referencing unpublished works or not?
Either "Accepted for Intl. Conf. on Whatever, 2018", or 
"To appear in Proc. Intl. Conf. on Whatever, 2018", or
"Intl. Conf. on Whatever, 2018, to appear".