Doug A. Bowman Sabine Coquillart Bernd Froehlich Michitaka Hirose Yoshifumi Kitamura Kiyoshi Kiyokawa Wolfgang Stürzlinger 20-36 2008 28 IEEE Computer Graphics and Applications 6 http://dx.doi.org/10.1109/MCG.2008.109 db/journals/cga/cga28.html#BowmanCFHKKS08