Changxing Dong Gerold Jäger Dirk Richter Paul Molitor Effective Tour Searching for TSP by Contraction of Pseudo Backbone Edges. 175-187 2009 AAIM http://dx.doi.org/10.1007/978-3-642-02158-9_16 conf/aaim/2009 db/conf/aaim/aaim2009.html#DongJRM09