1. “Brains, Machines, and Mathematics.”;Arbib,1966
2. Categories of (M, R)-systems;Arbib;Bull. Math. Biophys.,1966
3. Abstract biological systems as sequential machines—Behavioral reversibility;Demetrius;Bull. Math. Biophys.,1966
4. General theory of natural equivalence;Eilenberg;Trans. Amer. Math. Soc.,1945