1. Abrami, A.: 1971, in Proc. 1st CESRA-Conf., Utrecht.
2. Bekefi, G.: 1966, Radiation Processes in Plasmas, Wiley, New York.
3. Crawford, F. W.: 1965, Nuclear Fusion 5, 73.
4. Elgarøy, Ø.: 1961, Astrophys. Norv. 7, 123.
5. Elgarøy, Ø.: 1962, Inf. Bull. Solar Radio Obs., No. 9, 1962.