1. Hey, J. S.: Radio Astronomy. Monthly Notices 109, 179 (1949).
2. Hülst, H. C. van de: A Course in Radio Astronomy. Leiden 1951.
3. Lovell, B., and J. A. Clegg: Radio Astronomy. London 1952.
4. Nicolet, M.: Bruits solaires et cosmiques. Mem. Inst. Roy. Meteorolog. de Belgique, Vol. 35, 1949.
5. Pawsey, J. L., and S. F. Smerd: Solar Radio Emission. Kap. 7 in The Sun; ed. G. P. Kuiper: Chicago Univ. Press 1953.