Nsimama, P. ., and M. . Samiji. “Electrical Properties of DC Reactive Magnetron Sputtered ZnO:Al Films from Optical Spectra”. Tanzania Journal of Science, vol. 38, no. 2, Apr. 2021, pp. 39-52, https://tjs.udsm.ac.tz/index.php/tjs/article/view/350.