1. K. Kraus, States, Effects, and Operations: Fundamental Notions of Quantum Theory. Lecture Notes in Physics, vol. 190, Berlin: Springer-Verlag, 1983.
2. M.-D. Choi, “Completely positive linear maps on complex matrices,” Linear Algebra and Its Applications, vol. 10, pp. 285–290, 1975.
3. C. W. Helstrom, Quantum Detection and Estimation Theory. Mathematics in Science and Engineering, vol. 123, New York: Academic Press, 1976.
4. C. A. Fuchs, “Information Gain vs. State Disturbance in Quantum Theory,” submitted to Physica D special issue for PhysComp96. Also in LANL quantum physics archive quant-ph/9611010.
5. I. L. Chuang and Y. Yamamoto, “The Persistent Qubit,” to appear in Physical Review A, January 1997.