Towards a categorical semantics of type classes. - Barney P. Hilken; David E. Rydeheard (Fundam. Informaticae, 1992)

Towards a Proof Theory of Rewriting: The Simply Typed 2lambda-Calculus. - Barney P. Hilken (Theor. Comput. Sci., 1996)

A Theory of Classes: Proofs and Models. - Barney P. Hilken; David E. Rydeheard (Math. Struct. Comput. Sci., 1997)