V. K. KATIYAR, A. K. KATIYAR, and S. K. SRIVASTAVA. “Empirical Relationship of Sixth Order to Estimate Global Solar Radiation from Hours of Sunshine”. Journal of Agrometeorology, vol. 11, no. 2, Dec. 2009, pp. 97-101, doi:10.54386/jam.v11i2.1233.