Sani Aliyu, & Sabir Bello. (2017). The Performance Assessment of Hargreaves Model in Estimating Global Solar Radiation in Sokoto, Nigeria. International Journal of Advances in Scientific Research and Engineering (IJASRE), ISSN:2454-8006, DOI: 10.31695/IJASRE, 3(11), 6–15. https://doi.org/10.7324/IJASRE.2017.32542