6Laakko T and Mantyla M.Incremental constraint modeling in a feature modeling system [J].Computer Graphics Forum,1996,15(3):367-376.
7Roller D,Schonek F,Verreust A. Dimension-driven Geometry in CAD: A Survey, Theory and Practice of Geometric Modeling[M]. W Strasser, H-P Seidel(Eds.), Springer-Verlag, 1989.509-523.