1. Schpolski, E.W.: Atomphysik, I and IL VEB Berlin (1973/1974)
2. Pohl, R.W.: Elektrizitätslehre, 20. Auflage. Berlin, Heidelberg, New York: Springer 1967
3. Ingram, D.J.E.: Spectroscopy at Radio and Microwave Frequencies, 2nd Ed. London: Butterworth 1967
4. Zavoisky, E.: J. Phys. USSR 9, 211 (1945); see also: B. Rånby in: ESR Applications to Polymer Research, Nobel Symposium 22. Stockholm: Almquist & Wiksell 1973
5. Bovey, F.A.: High Resolution NMR of Macromolecules. New York: Academic Press 1972