8Clark James. Hierarchical Geometric Models for Visible Surface Algorithms[J]. Communications of the ACM, 1976, 19(10): 547-554.
9Peter Lindstrom, David Koller, William Ribarsky, et al. Real-Time Continuous Level-of-Detail Rendering of Height Fields [C]. Proceedings of SIGGRAPH' 96, 1996.
10Mark Duchaineau, Murray Wolinski, David E Sigeti, et al. ROAMing Terrain: Real-time Optimally Adap- ting Meshes [C]. IEEE Visualization' 97 Proceedings, 1997.
