Janis Fehr Marco Reisert Hans Burkhardt Fast and Accurate Rotation Estimation on the 2-Sphere without Correspondences. 239-251 2008 ECCV (2) http://dx.doi.org/10.1007/978-3-540-88688-4_18 conf/eccv/2008-2 db/conf/eccv/eccv2008-2.html#FehrRB08