Xikun Liang Mai Ali Nur Brian Wyvill Modeling the Structure of the Sea Anemone and the Sea Star Using Hierarchical Implicit Surfaces. 265-275 2001 conf/pg/2001 Pacific Conference on Computer Graphics and Applications http://csdl.computer.org/comp/proceedings/pg/2001/1227/00/12270265abs.htm db/conf/pg/pg2001.html#LiangNW01