@article{JGAA_2006_10_1_a1,
     author = {Hans Bodlaender and Thomas Wolle and Arie Koster},
     title = {Contraction and {Treewidth} {Lower} {Bounds}},
     journal = {Journal of Graph Algorithms and Applications},
     pages = {5--49},
     publisher = {mathdoc},
     volume = {10},
     number = {1},
     year = {2006},
     doi = {10.7155/jgaa.00117},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.7155/jgaa.00117/}
}