WINTER: WAMS in Tim Expression Reduction. - Damir Jamsek; Kevin J. Greene; Shiu-Kai Chin; Paul R. Humenn (NACLP, 1989)

Simulations between Programs as Cellular Automata. - Howard A. Blair; Fred Dushin; Paul R. Humenn (LPNMR, 1997)

A Continuum of Discrete Systems. - Howard A. Blair; Jagan Chidella; Fred Dushin; Audrey Ferry; Paul R. Humenn (Ann. Math. Artif. Intell., 1997)