Mellit, A. S. “The Case Where the Sum of Three Partial Reflections Is Equal to Zero”. Ukrains’kyi Matematychnyi Zhurnal 55, no. 9 (September 25, 2003): 1277–1283. Accessed April 11, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/4001.