Sumanta Guha Joint Separation of Geometric Clusters and the Extreme Irregularities of Regular Polyhedra. 229-243 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2914&spage=229 2003 conf/fsttcs/2003 FSTTCS db/conf/fsttcs/fsttcs2003.html#Guha03