**12. References**

Angstrom, A. K (1924). Solar and atmospheric radiation, *J. Roy Meteorol.Soc*. 50, pp. 121 -126. Babatunde, E. B (1995) Correlation of fraction of sun shine hours with clearness index and cloudiness index at a tropical station Ilorin, *Nigeria. Nig.J. of Solar Energy* Vol 13, pp 22 -27

