1. T. G. Cowling, Mon. Notic. Roy. Astron. Soc. 105, 166 (1945).
2. E. F. Borra, Astrophys. J. Lett. 249, L39 (1981).
3. D. N. Brown, J. D. Landstreet, and I. Thompson, 23-d Coll., Liege (1981), p. 195.
4. P. North and N. Cramer, Astron. Astrophys. Suppl. Ser. 58, 387 (1984).
5. Yu. V. Glagolevskij, V. G. Klochkova, and I. M. Kopylov, Magnetic Stars [in Russian], Salaspils (1984), p. 82.