1. [1] B. Mielnik, Analytic functions of the displacement operator, PhDhesis, Cinvestav, Mexico City, 1964.
2. [2] B. Mielnik et al., Jerzy Plebanski: he quest for new worlds, in Topics in Mathematical Physics, General Relativity and Cosmology in Honor of Jerzy Plebanski, ed. H. García-Compeán et al., p. 3,World Scientific 2006
3. [3] B. Mielnik, Geometry of quantum states, Comm. Math. Phys. 9, 55 (1968).
4. [4] B. Mielnik, Theory of filters, Comm. Math. Phys. 15, 1 (1969).
5. [5] I. Bengtsson and K. Życzkowski, Geometry of Quantum States, Cambridge University Press, Cambridge, 2006.