Emmanuel Chinweikpe Obuah, and Tamuno-Omie Joyce Alalibo. “Effect of Change in Tilt Angle on the Performance of Photovoltaic Systems”. Journal of Power Electronics and Devices, vol. 6, no. 1, Jan. 2020, pp. 10-17, http://matjournals.co.in/index.php/JOPED/article/view/3786.