M. A. Gopalan, S. Vidhyalaksmi, N. Thiruniraiselvi, and R. Presenna. 2015. “Special Pythagorean Triangles and 6 Digit Dhuruva Number”. International Journal of Mathematics And Its Applications 3 (2):149-54. https://ijmaa.in/index.php/ijmaa/article/view/432.