1. [1] J. ADAMEK, Realization theory for automata in categories, J. Pure Appl. Alg. 9 (1977), 281-296.
2. [2] B. D. O. ANDERSON, M. A. ARBIB and E. G. MANES, Foundations of system theory, Lecture Notes in Economics and Mathematical Systems, Springer-Verlag, New York, 115 (1976).
3. [3] M. A. ARBIB and E. G. MANES, Machines in a category, An expository introduction, SIAM 16 (1974), 163-192.
4. [4] M. A. ARBIB and E. G. MANES Arrow, structures, and functors, Academic Press, New York, 1975.
5. [5] M. BARR, Right exact functors, J. Pure Appl. Alg. 4 (1974), 1-8.