Animating Programs Using Smalltalk. - Ralph L. London; Robert Duisberg (Computer, 1985)

Constraint-Based Tools for Building User Interfaces. - Alan Borning; Robert Duisberg (ACM Trans. Graph., 1986)

Constraint Hierarchies. - Alan Borning; Robert Duisberg; Bjørn N. Freeman-Benson; Axel Kramer; Michael Woolf (OOPSLA, 1987)

Animation Using Temporal Constraints: An Overview of the Animus System. - Robert Duisberg (Hum. Comput. Interact., 1987)