1. Belcher, J. W.: 1971,Astrophys. J. 168, 509.
2. Bridle, A. H.: 1982, in D. S. Heeschen and C. M. Wade (eds.),Extragalactic Radio Sources, D. Reidel Publ. Co., Dordrecht, Holland, p. 121.
3. Hollweg, J. V.: 1973,Astrophys. J. 181, 547.
4. Holzer, T. E.: 1977,J. Geophys. Res. 82, 23.
5. Holzer, T. E.: 1977, in L. J. Lanzerotti, C. F. Kennel, and E. N. Parker (eds.),Solar System Plasma Physics, Vol. 1, North-Holland Publ. Co., Amsterdam, p. 105.