Bondarenko, V. M., and M. V. Stepochkina. “$(\min, \max)$-Equivalence of Posets and Nonnegative Tits Forms”. Ukrains’kyi Matematychnyi Zhurnal, vol. 60, no. 9, Sept. 2008, pp. 1157–1167, https://umj.imath.kiev.ua/index.php/umj/article/view/3234.