1. Björner, A. and Brenti, F., Combinatorics of Coxeter Groups, Graduate Texts in Mathematics, 231, Springer, New York, 2005
2. Burago, D., Ferleger, S. and Kononenko, A., Collisions in semi-dispersing billiard on Riemannian manifold, Proceedings of the International Conference on Topology and its Applications (Yokohama, 1999), Topology Appl., 122(1–2), 2002, 87–103
3. Gal'perin, G. A., On systems of locally interacting and repelling particles moving in space (in Russian), Trudy Moskov. Mat. Obshch., 43, 1981, 142–196; English translation in Trans. Moscow Math. Soc., 1983(1), 1983, 159–214
4. Murphy, T. J. and Cohen, E. G. D., Maximum number of collisions among identical hard spheres, J. Statist. Phys., 71(5–6), 1993, 1063–1080
5. Murphy, T. J. and Cohen, E. G. D., On the sequences of collisions among hard spheres in infinite space, Hard Ball Systems and the Lorentz Gas, D. Sz´asz (ed.), Encycl. Math. Sci., 101(2), Springer, Berlin, 2000, 29–49