Jorge Tavares Francisco Baptista Pereira Ernesto Costa 416-417 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3103&spage=416 2004 conf/gecco/2004-2 GECCO (2) db/conf/gecco/gecco2004-2.html#TavaresPC04