1. Bohlin, J. D. and Rubenstein, D. M.: 1975, NOAA World Data Center A for Solar Terrestrial Phys., Report UAG-51.
2. Dodge, J. C.: 1974, Report No. SN-5, Radio Astron. Obsvy. of U. of Colorado, Boulder, CO, USA. (For a discussion of these data, see Dodge, J. C.: 1975, Solar Phys. 42, 445–459.)
3. Dulk, G. A., Smerd, S. F., MacQueen, R.M., Gosling, J. T., Magun, A., Stewart, R. T., Sheridan, K. V., Robinson, R. D., Jacques, S.: 1976, Solar Phys. 49, 369.
4. Eddy, J. A.: 1974, Astron and Astrophys. 34, 235–240.
5. Feldman, W. C., Asbridge, J. R., Bame, S. J., Gosling, J. T.: 1977 chapter in The Solar Output and Its Variation, 0. R. White, ed., Associated Univ. Press, Boulder, Colorado U.S.A.