Who is the Author: Conference paper editors

Always check the title page for the name of the author responsible for editing the proceedings. If you cannot find these, then start off your reference with the name of the Conference. 

To help trace the document always put in the place and date of the event.

Cunningham, S. (ed.), 1993, Computer Graphics: SIGGRAPH 93 conference proceedings, Anaheim, California, 1-6 August, 1993. New York: The Association of Computing Machinery.