D. A. Etemad, “A study on tensor product surfaces in low-dimensional Euclidean spaces”, Ukr. Mat. Zhurn., vol. 64, no. 12, pp. 1630–1640, Dec. 2012, Accessed: Apr. 13, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/2687