Yuichi Asahiro Jesper Jansson Eiji Miyano Hirotaka Ono Kouhei Zenmyo Approximation Algorithms for the Graph Orientation Minimizing the Maximum Weighted Outdegree. 167-177 2007 conf/aaim/2007 AAIM http://dx.doi.org/10.1007/978-3-540-72870-2_16 db/conf/aaim/aaim2007.html#AsahiroJMOZ07