Claude Lattaud Co-evolution in Artificial Ecosystems: Competition and Cooperation Using Allellopathy. 319-330 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2936&spage=319 2003 conf/ae/2003 Artificial Evolution db/conf/ae/ae2003.html#Lattaud03