Thongmoo, Montri, Sasitorn Putjuso, and Thana Nuntigrangjana. 2021. “The non-negative integer solutions of Diophantine equation 15^x + 51^y = z^2”. Journal of Science and Science Education (JSSE) 4 (2):172-77. https://so04.tci-thaijo.org/index.php/JSSE/article/view/254507.