1. J. A. Stratton, Electromagnetic Theory, McGraw-Hill, New York (1941).
2. E. N. Parker, Cosmical Magnetic Fields: Their Origin and Their Activity, Clarendon Press, Oxford (1979).
3. A. van Vleuten, Koninklijk Ned. Meteor. Instit., Utrecht, No. 102, 5–30 (1917).
4. N. P. Ben’kova, Quiet Solar-Daily Variations of the Earth’s Magnetism [in Russian], Gidrometeoizdat, Moscow-Leningrad (1941).
5. D. N. Chetaev, Fiz. Zemli, No. 2, 52–55 (1970).