A Constraint-Based Method for Sculpting Free-Form Surfaces. - Paul Michalik; Beat D. Brüderlin (Geometric Modelling, 1999)

Declarative Geometric Modeling with Constraints. - Beat D. Brüderlin; Ulf Döring; Rüdiger Klein; Paul Michalik (CAD, 2000)

Sketch- and constraint-based design of B-spline surfaces. - Paul Michalik; Dae-Hyun Kim; Beat D. Brüderlin (Symposium on Solid Modeling and Applications, 2002)

Constraint-based design of B-spline surfaces from curves. - Paul Michalik; Beat D. Brüderlin (Symposium on Solid Modeling and Applications, 2004)