1. Rapp, D., Englander-Golden, P.: J. Chem. Phys. 43 (1965) 1464.
2. Vriens, L.: Physica 31 (1965) 395.
3. Calvert, J.G., Pitts, J.N.: Photochemistry, New York: Wiley and Sons, 1966.
4. Lengyel, B.A.: Introduction to Laser Physics, New York: Wiley and Sons, 1966.
5. Robinson, E.J., Geltmann, S.: Phys. Rev. 153 (1967) 4.