1. R. D. Levine, Scientific American 246 #1, 118 (1982).
2. D. Schmandt-Besserat, Scientific American 238 #6, 50 (1978).
3. H. H. Goldstine, The Computer from Pascal to von NeumannPrinceton University Press (1972).
4. L. M. Branscomb, Science 215, 755 (1982).
5. M. S. Pittler, D. M. Powers, D. L. Schnabel, IBM J. Res. Develop. 26, 2 (1982).