1. Gallager, R.G.: Information Theory and Reliable Communication, Wiley, New York, 1968 (Chapter 2).
2. Pfaffelhuber, E. and Güttinger, W.: Kybernetik (Informations-, Systemund Nachrichtentheorie) I,II, University of Munich Lecture Notes, 1967/68.
3. Barlow, H.B.: Trigger features, adaptation and economy of impulses. In: Information Processing in the Nervous System, ed. by K.N. Leibovic. Springer-Verlag, New York, 1969.
4. Barlow, H.B.: The coding of sensory messages. In: Current Problems in Animal Behavior, ed. by W.H. Thorpe and O.L. Zangwill. Cambridge University Press, Cambridge, 1961.
5. Barlow, H.B.: Redundancy and perception, this volume.