Susan Stepney Robert E. Smith Jonathan Timmis Andrew M. Tyrrell Towards a Conceptual Framework for Artificial Immune Systems. 53-64 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3239&spage=53 2004 conf/icaris/2004 ICARIS db/conf/icaris/icaris2004.html#StepneySTT04