Thomas Eiter Michael Fink Hans Tompits Stefan Woltran Simplifying Logic Programs Under Uniform and Strong Equivalence. 87-99 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2923&spage=87 2004 conf/lpnmr/2004 LPNMR db/conf/lpnmr/lpnmr2004.html#EiterFTW04