Bastin Tony Roy Savarimuthu Maryam Purvis Martin K. Purvis Stephen Cranefield Social Norm Emergence in Virtual Agent Societies. 18-28 2008 DALT http://dx.doi.org/10.1007/978-3-540-93920-7_2 conf/dalt/2008 db/conf/dalt/dalt2008.html#SavarimuthuPPC08