Constraint objects: integrating constraint definition and graphical interaction. - Ching-yao Hsu; Beat D. Brüderlin (Solid Modeling and Applications, 1993)

A Hybrid Constraint Solver Using Exact and Iterative Geometric Constructions. - Ching-yao Hsu; Beat D. Brüderlin (CAD Systems Development, 1995)

A Degree-of-Freedom Graph Approach. - Ching-yao Hsu; Beat D. Brüderlin (Geometric Modeling, 1997)

A Constraint-Based Manipulator Toolset for Editing 3D Objects. - Ching-yao Hsu; G. Alt; Z. Huang; Ekkehard Beier; Beat D. Brüderlin (Symposium on Solid Modeling and Applications, 1997)

Inferring 3D models from freehand sketches and constraints. - Lynn Eggli; Ching-yao Hsu; Beat D. Brüderlin; Gershon Elber (Comput. Aided Des., 1997)