Christoph Beierle Marija Kulas Manfred Widera A Pragmatic Approach to Pre-testing Prolog Programs. 294-308 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3392&spage=294 2004 conf/wlp/2004 INAP/WLP db/conf/wlp/wlp2004.html#BeierleKW04