Bondarenko VM, Stepochkina MV. Description of posets critical with respect to the nonnegativity of the quadratic Tits form. Ukr. Mat. Zhurn. [Internet]. 2009 May 25 [cited 2025 Dec. 5];61(5):611-24. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/3045