1. Attneave, F. Perception and related areas. In S. Koch (Ed.),Psychology: A study of a science. New York: McGraw Hill, Vol. 4, 1962. Pp. 619–659.
2. Bomba, J. S. Alpha-numeric character recognition using local operations.Proc. east. joint Comput. Conf., 1959, 16, 218–224.
3. Conrad, R. Acoustic confusions in immediate memory.Brit. J. Psychol., 1964, 55, 75–84.
4. Doyle, W. Recognition of sloppy, hand-printed characters.Proc. west. joint Comput. Conf., 1960, 17, 133–142.
5. Fischler, M., Mattson, R. L., Firschein, O., &Healy, L. D. An approach to general pattern recognition.IRE Trans, inform. Theory, 1962, 8, 64–73.