EmetsO. A., NedobachiiS. I., and RoskladkaО. V. “Irreducible System of Constraints for a General Polyhedron of Arrangements”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 55, no. 1, Jan. 2003, pp. 3-11, https://umj.imath.kiev.ua/index.php/umj/article/view/3882.