Pedro Berrizbeitia S. Müller Hugh C. Williams Pseudocubes and Primality Testing. 102-116 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3076&spage=102 2004 conf/ants/2004 ANTS db/conf/ants/ants2004.html#BerrizbeitiaMW04