1. Alfvén, H., “Cosmical Electrodynamics”, chap. 4 (Oxford, 1950).
2. Walén, C., Ark. f. mat., astr. o. fysik, 30 A, No. 15 (1944). Lundquist, S., Phys. Rev., 76, 1805 (1949).
3. Alfvén, H., “Cosmical Electrodynamics”, 151 (Oxford, 1950).
4. Richtmyer, R. D., and Teller, E., Phys. Rev., 75, 1729 (1949). Fermi, E., Phys. Rev., 75, 1169 (1949). Alfvén, H., Phys. Rev., 75, 1732 (1949); ibid., 77, 375 (1950).
5. Åström, E. (see preceding communication).