B. Han, Y. Wang, and X. Jia. Computer, Mechatronics, Control and Electronic Engineering (CMCE), 2010 International Conference on, 6, page 165 -168. (August 2010)
A. Neubeck, and L. Van Gool. Proceedings of the 18th International Conference on Pattern Recognition - Volume 03, page 850--855. Washington, DC, USA, IEEE Computer Society, (2006)