Mariusz Momotko Kazimierz Subieta Process Query Language: A Way to Make Workflow Processes More Flexible. 306-321 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3255&spage=306 2004 conf/adbis/2004 ADBIS db/conf/adbis/adbis2004.html#MomotkoS04