Principles of automated theorem proving. - David A. Duffy (Wiley, 1991)

A Framework for Requirements Analysis Using Automated Reasoning - David A. Duffy; Craig MacNish; John A. McDermid; Philip Morris (CAiSE, 1995)

Closure Induction in a Z-Like Language. - David A. Duffy; Jürgen Giesl (ZB, 2000)

Reasoning Inductively about Z Specifications via Unification. - David A. Duffy; Ian Toyn (ZB, 2000)

On Mutually Recursive Free Types in Z. - Ian Toyn; Samuel H. Valentine; David A. Duffy (ZB, 2000)