Verification of an Audio Control Protocol. - Doeko Bosscher; Indra Polak; Frits W. Vaandrager (FTRTFT, 1994)

Algebraic Proof Assistants in HOL. - Rix Groenboom; Chris Hendriks; Indra Polak; Jan Terlouw; Jan Tijmen Udding (MPC, 1995)

Normal Form in DI-Algebra with Recursion. - Paul G. Lucassen; Indra Polak; Jan Tijmen Udding (ASYNC, 1997)