Gregory J. Duck Maria J. García de la Banda Peter J. Stuckey Compiling Ask Constraints. 105-119 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3132&spage=105 2004 conf/iclp/2004 ICLP db/conf/iclp/iclp2004.html#DuckBS04