1. L. S. Ballentine:Rev. Mod. Phys.,42, 358 (1970).
2. M. Jammer:The Philosophy of Quantum Mechanics (New York, N. Y., 1974).
3. In quantum mechanics one would say reprepare, while in hidden variable theories one would say randomize over the uncontrolled variables.
4. This definition is weaker than the definition used in stochastic processes. We do not use the latter definition only because it would require us to define several additional terms not necessary to this article.
5. J. S. Bell:Physics,1, 195 (1964).