1. Jacob D. Bekenstein,Phys. Rev. Lett. 46:623 (1981).
2. Charles H. Bennett,IBM J. Res. Dev. 17:525 (1973).
3. Hans J. Bremerman, ?Part I. Limitations on Data Processing Arising From Quantum Theory,? inSelf-Organizing Systems, M. C. Yovits, G. T. Jacobi, and G. D. Goldstein, eds. (Spartan Books, Washington, D.C., 1967).
4. Hans J. Bremerman, ?Energy and Entropy Costs in Information Transfer and Computing,? Preprint to appear in Proceedings of Conference on Physics of Computation, MIT, May 6?8, 1981.
5. David Deutsch,Phys. Rev. Lett. 48:286 (1982).