OstapenkoV. V., and FininG. S. “Methods for the Elimination of Unknowns from Systems of Linear Inequalities and Their Applications”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 53, no. 1, Jan. 2001, pp. 50-56, https://umj.imath.kiev.ua/index.php/umj/article/view/4220.