Arlette van Wissen Jurriaan van Diggelen Virginia Dignum The effects of cooperative agent behavior on human cooperativeness. 1179-1180 2009 AAMAS (2) http://doi.acm.org/10.1145/1558109.1558200 conf/atal/2009-2 db/conf/atal/aamas2009-2.html#WissenDD09