(ASA Style Guide 2014 section 4.3.2 p. 55, and appendix p. 113)
(Author1 Last name and Author2 Last name Year of publication)
(Petts and Knoester 2016)
Author1 Last name, First name, and Author2 First name Last name. Year of presentation. "Title of Paper." Presented at, Month date, Location.
Petts, Richard J., and Christ Knoester. 2016. "Paternity Leave-Taking in the Unites States." Presented at the annual meeting of the American Sociological Association, August 22, Seattle.