Airat Bekmetjev Graham Brightwell Andrzej Czygrinow Glenn Hurlbert Thresholds for families of multisets, with an application to graph pebbling. 21-34 2003 269 Discrete Mathematics 1-3 http://dx.doi.org/10.1016/S0012-365X(02)00745-8 db/journals/dm/dm269.html#BekmetjevBCH03