1. Alfvén, H. and Carlqvist, P.: 1967, Solar Phys. 1, 220.
2. Alfvén, H. and Fälthammar, C.-G.: 1963, Cosmical Electrodynamics, 2nd ed., Clarendon Press, Oxford.
3. Allen, C.: 1963, Astrophysical Quantities, 2nd ed., Athlone Press, University of London.
4. Child, D.: 1911, Phys. Rev. 32, 492.
5. Cowling, T.: 1957, Magnetohydrodynamics, Interscience Publishers, Inc., New York.