1. Haken, H., Roy, R.: Laser Theory. Springer, Berlin (1984)
2. Sargent III, M., Scully, M.O., Lamb Jr., W.E.: Laser Physics. Addison-Wesley, Reading (1974)
3. Loulsell, W.H.: Quantum Statistical Properties of Radiation. Willey, New York (1973)
4. Zhu, S., Yin, J.: Saturation effect in a laser at steady state. Phys. Rev. A 45(7), 4969–4973 (1992)
5. Risken, H.: The Fokker-Planck Equation. Springer, Berlin (1984)