1. Allen, C. W.: 1973,Astrophysical Quantities 3rd ed., University of London Press, London.
2. Al-Naimiy, H.: 1978,Astrophys. Space Sci. 53, 181.
3. Baliunas, S. L. and Vaughan, A. H.: 1985,Ann. Rev. Astr. Astrophys. 23, 379.
4. Banks, T.: 1989, M.Sc. Thesis, Victoria University of Wellington, New Zealand (unpublished).
5. Bevington, P. R.: 1969,Data Reduction and Error Analysis for the Physical Sciences, McGraw-Hill, New York.