Lee Spector Jon Klein Chris Perry Mark Feinstein Emergence of Collective Behavior in Evolving Populations of Flying Agents. 61-73 2003 conf/gecco/2003-1 GECCO http://link.springer.de/link/service/series/0558/bibs/2723/27230061.htm db/conf/gecco/gecco2003-1.html#SpectorKPF03