Hikoe Enomoto Kyoji Ohba Katsuhiro Ota Junko Sakamoto Choice number of some complete multi-partite graphs. 55-66 2002 244 Discrete Mathematics 1-3 http://dx.doi.org/10.1016/S0012-365X(01)00059-0 db/journals/dm/dm244.html#EnomotoOOS02