Alexander M. Bronstein Michael M. Bronstein Ron Kimmel Expression-Invariant 3D Face Recognition. 62-69 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2688&spage=62 2003 conf/avbpa/2003 AVBPA db/conf/avbpa/avbpa2003.html#BronsteinBK03