Akinnawo, O. O., O. C. Adebayo, A. G. Usifo, and A. K. Ogundele. “Fuzzy Model, Neural Network and Empirical Model for the Estimation of Global Solar Radiation for Port-Harcourt, Nigeria”. Theory and Applications of Mathematical Science Vol. 1, Jan. 2020, pp. 51-59, https://stm1.bookpi.org/index.php/tams-v1/article/view/27.