1. A.A. Dabagyan, M.E. Movsessyan, T.H. Ovakimyan, S.V. Shmavonyan: Zh. Eksp. Teor. Fiz. 85, 1203 (1983)
2. A.A. Dabagyan, M.E. Movsessyan, T.H. Ovakimyan, S.V. Shmavonyan: Izv. Akad. Nauk SSSR Fiz. 47, 1609 (1983)
3. S.N. Atutov, A.I. Plekhanov, A.M. Shalagin: Opt. Spectrosk. 56, 215 (1984)
4. J. Czub, J. Fiutak, W. Miklaszewski: Z. Phys. D 3, 23 (1986)
5. J.L. Carlsten, A. Szoke, M.G. Raymer: Phys. Rev. A 15, 1079 (1977)