Carlo Ferrari Concettina Guerra Geometric Methods for Protein Structure Comparison. 57-82 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2666&spage=57 2003 conf/msps/2003 Mathematical Methods for Protein Structure Analysis and Design db/conf/msps/msps2003.html#FerrariG03