1. A. Lechet, Nuclear Induction [Russian translation], IIL, Moscow, 1963.
2. P. Geissler and H. Pfeifer, Zeitschrift für Naturforschung, 12 a, 70, 1957.
3. A. Abragam, Principles of Nuclear Magnetism [Russian translation], IIL, Moscow, 1963.
4. G. V. Skrotskii and V. T. Shmatov, ZhETF,34, 740, 1958.