A. Torralba, K. Murphy, W. Freeman, and M. Rubin. Computer Vision, 2003. Proceedings. Ninth IEEE International Conference
on, page 273--280 vol.1. (2003)
R. Madsen, S. Sigurdsson, L. Hansen, and J. Larsen. Pattern Recognition, 2004. ICPR 2004. Proceedings of the 17th International
Conference on, (23-26 Aug. 2004)