Arlindo Silva Ana Neves Ernesto Costa SAPPO: A Simple, Adaptable, Predator Prey Optimiser. 59-73 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2902&spage=59 2003 conf/epia/2003 EPIA db/conf/epia/epia2003.html#SilvaNC03