Hongguang Fu Rongqiu Wu Weimin Wang Junhua Yang Active Contour Model based on Dynamic Extern Force and Gradient Vector Flow. 863-867 2008 BMEI (1) http://doi.ieeecomputersociety.org/10.1109/BMEI.2008.252 conf/bmei/2008-1 db/conf/bmei/bmei2008-1.html#FuWWY08