1. Pezzé, L., Smerzi, A.: Phys. Rev. Lett. 102, 100401 (2009)
2. Helstrom, C.W.: Quantum Detection and Estimation Theory. Academic Press, New York (1976), Chap. VIII
3. Holevo, A.S.: Probabilistic and Statistical Aspect of Quantum Theory. North-Holland, Amsterdam (1982)
4. Wootters, W.K.: Phys. Rev. D 23, 357 (1981)
5. Braunstein, S.L., Caves, C.M.: Phys. Rev. Lett. 72, 3439 (1994)