Machiel van der Bijl Arend Rensink Jan Tretmans Compositional Testing with ioco. 86-100 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2931&spage=86 2003 conf/fates/2003 FATES db/conf/fates/fates2003.html#BijlRT03