Alexandre Petrenko Nina Yevtushenko Jiale Huo Testing Transition Systems with Input and Output Testers. 129-145 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2644&spage=129 2003 conf/pts/2003 TestCom db/conf/pts/testcom2003.html#PetrenkoYH03