1. A. Abragam, The Principles of Nuclear Magnetism (Clarendon Press, Oxford, 1961; Inostrannaya Literatura, Moscow, 1963).
2. K. A. Valiev and L. D. Éskin, Opt. Spektrosk. 12, 758 (1962).
3. E. N. Ivanov, Zh. Éksp. Teor. Fiz. 45, 1509 (1963) [Sov. Phys. JETP 18, 1041 (1963)].
4. F. I. Bashirov, Yu. L. Popov, K. S. Saikin, and R. A. Dautov, Zh. Éksp. Teor. Fiz. 62(5), 1803 (1972) [Sov. Phys. JETP 35, 937 (1972)].
5. P. Rigny, Physica (Amsterdam) 59, 707 (1972).