1. Braid, I.C., On storing and changing shape information, Computer Graphics, 12(3):252–256, 1978 (SIGGRAPH ’78).
2. van Emmerik, M.J.G.M., Rappoport, A., Rossignac, J., ABCSG: a hypertext approach for interactive design of solid models, assemblies and patterns, to be published in The Visual Computer, 1991.
3. de Floriani, L., Falcidieno, B., A hierarchical boundary model for solid object representation, ACM Transactions On Graphics 7(1):42–60,1988.
4. Hoffmann, C., Geometric and Solid Modling: an Introduction, Morgan Kaufmann, 1989.
5. Lee, K., Gossard, D.C., A hierarchical data structure for representing assemblies: part 1, Computer-Aided Design 17(1):15–19, 1985.