Bistra N. Dilkina Carla P. Gomes Yuri Malitsky Ashish Sabharwal Meinolf Sellmann Backdoors to Combinatorial Optimization: Feasibility and Optimality. 56-70 2009 CPAIOR http://dx.doi.org/10.1007/978-3-642-01929-6_6 conf/cpaior/2009 db/conf/cpaior/cpaior2009.html#DilkinaGMSS09