1. Allen, C.W.: 1963: Astrophysical Quantities, 2nd ed. Attlone Press, London.
2. De Jager, C.: 1959, in Handbuch der Physik, vol. 52. Springer Verlag, Berlin.
3. DeJager, C.: 1967, in Electromagnetic Radiation in Space (ed. by J.G. Emming). Reidel, Dordrecht. See also Solar Physics 2, 347.
4. DeJager, C. and Legrand, J.P.: 1965, SPARMO bulletin 3, 1?3.
5. Kundu, M.R.: 1965, Solar Radio Astronomy. Interscience Publishers, New York.