Martin Capek Rainer Wegenkittl Andreas König Werner Jaschke Reinhart Sweeny Reto J. Bale Multimodal Medical Volume Registration Based on Spherical Markers. 17-24 2001 WSCG http://wscg.zcu.cz/wscg2001/Papers_2001/R15.pdf db/conf/wscg/wscg2001.html#CapekWKJSB01