1. Sander, Perdo V., Synder, John, Gortler, Steven J. and Hoppe, Hugues. “Texture Mapping Progressive Meshes.”. Proceedings of the 28th Annual Conference on Computer Graphics and Interactive Techniques. pp.409–416. New York: ACM. [Sander et al. 01]
2. Abelian Groups that are unions of proper subgroups