Ying Bai Xiao Han Jerry L. Prince Octree Grid Topology Preserving Geometric Deformable Model for Three-Dimensional Medical Image Segmentation. 556-568 2007 conf/ipmi/2007 IPMI http://dx.doi.org/10.1007/978-3-540-73273-0_46 db/conf/ipmi/ipmi2007.html#BaiHP07