V. K. Medvedev, “Coordinate system and combinatorial objects (an example of a generalized quadrangle)”, Ukr. Mat. Zhurn., vol. 46, no. 5, pp. 516–523, May 1994, Accessed: Feb. 17, 2026. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/5715