Shalini, T. K., et al. “Effect of Al-Doping on the Structure and Optical Properties of ZnO Thin Films by Sol-Gel Spin Coating”. International Journal of Research in Engineering, Science and Management, vol. 8, no. 8, Aug. 2025, pp. 52-56, https://journal.ijresm.com/index.php/ijresm/article/view/3338.