Tutov A. A., and Futorny V. M. “On Decompositions of the Systems of Roots of Кас-Moody Algebras of Rank 2 ”. Ukrains’kyi Matematychnyi Zhurnal 44, no. 12 (December 4, 1992): 1712-1715. Accessed July 27, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/8196.