1. Acton, L. W., Catura, R. C., Meyerott, H. J., and Culhane, J. L.: 1971, Nature
223, 75.
2. Allen, C. W.: 1963, Astrophysical Quantities, 2nd ed., Athlone Press, London.
3. Allen, J. and Dupree, A. K.: 1969, Astrophys. J.
155, 27.
4. Argo, H. V., Bergey, J. A., Evans, W. D., and Singer, S.: 1968, Solar Phys.
5, 531.
5. Austin, W. E., Purcell, J. D., and Tousey, R.: 1962, Astron. J.
67, 110.