Florian Diedrich Rolf Harren Klaus Jansen Ralf Thöle Henning Thomas Approximation Algorithms for 3D Orthogonal Knapsack. 34-45 2007 conf/tamc/2007 TAMC http://dx.doi.org/10.1007/978-3-540-72504-6_3 db/conf/tamc/tamc2007.html#DiedrichHJTT07