Jianfeng Lu Terry Caelli Jing-Yu Yang A Comparison of Least Squares and Spectral Methods for Attributed Graph Matching. 325-333 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3138&spage=325 2004 conf/sspr/2004 SSPR/SPR db/conf/sspr/sspr2004.html#LuCY04