Paolo Cignoni Leila De Floriani Paola Magillo Enrico Puppo Roberto Scopigno Selective Refinement Queries for Volume Visualization of Unstructured Tetrahedral Meshes. 29-45 2004 10 IEEE Trans. Vis. Comput. Graph. 1 http://csdl.computer.org/comp/trans/tg/2004/01/v0029abs.htm db/journals/tvcg/tvcg10.html#CignoniFMPS04