Lyuba Alboul Optimising Triangulated Polyhedral Surfaces with Self-intersections. 48-72 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2768&spage=48 2003 conf/ima-ms/2003 IMA Conference on the Mathematics of Surfaces db/conf/ima-ms/ima-ms2003.html#Alboul03