Naoya Ohta Ken-ichi Kanatani Optimal Estimation of Three-Dimensional Rotation and Reliability Evaluation. 175-187 http://link.springer.de/link/service/series/0558/bibs/1406/14060175.htm 1998 conf/eccv/1998-1 ECCV (1) db/conf/eccv/eccv1998-1.html#OhtaK98