Marek Cygan Jesper Nederlof Marcin Pilipczuk Michal Pilipczuk Johan M. M. van Rooij Jakub Onufry Wojtaszczyk Solving connectivity problems parameterized by treewidth in single exponential time http://arxiv.org/abs/1103.0534 2011 CoRR abs/1103.0534 db/journals/corr/corr1103.html#abs-1103-0534