Logic Programs with Functions and Default Values.

Pedro Cabalar David Lorenzo Logic Programs with Functions and Default Values. 294-306 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3229&spage=294 2004 conf/jelia/2004 JELIA db/conf/jelia/jelia2004.html#CabalarL04