Kedar Dhamdhere Anupam Gupta R. Ravi Approximation Algorithms for Minimizing Average Distortion. 93-111 2006 39 Theory Comput. Syst. 1 http://dx.doi.org/10.1007/s00224-005-1259-6 db/journals/mst/mst39.html#DhamdhereGR06