Dutta, A. ., J. . Biswas, S. . Roychowdhury, and S. . Neogi. “Optimum Tilt Angles for Manual Tracking of Photovoltaic Modules”. Distributed Generation &Amp; Alternative Energy Journal, vol. 31, no. 02, Jan. 2016, pp. 7-35, doi:10.13052/dgaej2156-3306.3121.