See also: N.G. Basov, G.M. Strakhovskii, A.N. Oraevskii, O.N. Krokhin, G.B. Malykin, I.D. Novikov, A.A. Logunov, V.I. Ritus
PACS: 06.20.fb, 06.30.Ft, 03.30.+p, 04.20.-q