K. Tsamaase, J. Sakala, K. Motshidisi, E. Rakgati, I. Zibani, and E. Matlotse "Performance Adjustment Factor for Fixed Solar PV Module", Advances in Science, Technology and Engineering Systems Journal, vol. 7, no. 4, pp. 98–104, 2022, doi: 10.25046/aj070413.