BondarenkoV. M., and StepochkinaM. V. “Description of Posets Critical With Respect to the Nonnegativity of the Quadratic Tits Form”. Ukrains’kyi Matematychnyi Zhurnal 61, no. 5 (May 25, 2009): 611-624. Accessed July 27, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/3045.