Thomas Brox Andrés Bruhn Nils Papenberg Joachim Weickert High Accuracy Optical Flow Estimation Based on a Theory for Warping. 25-36 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3024&spage=25 2004 conf/eccv/2004-4 ECCV (4) db/conf/eccv/eccv2004-4.html#BroxBPW04