Yoshikazu Washizawa Kenji Hikida Toshihisa Tanaka Yukihiko Yamashita Kernel Relative Principal Component Analysis for Pattern Recognition. 1105-1113 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3138&spage=1105 2004 conf/sspr/2004 SSPR/SPR db/conf/sspr/sspr2004.html#WashizawaHTY04