1. McLean, D. J., Sheridan, K. V., Stewart, R. T., and Wild, J. P., Nature, 234, 140 (1971).
2. Rosenberg, H., Astron. Astrophys., 9, 159 (1970).
3. Rosenberg, H., Proc. of the Second Committee Eur. Sol. Radio Astron. Meeting (Trieste, 1972).
4. Slottje, C., Rep. of the First Committee Eur. Sol. Radio Astron. Meeting (Utrecht, 1971).
5. Abrami, A., Rep. of the First Committee Eur. Sol. Radio Astron. Meeting (Utrecht, 1971).