@TechReport{MuellerSzeider, author = {Moritz M\"{u}ller and Stefan Szeider}, title = {The Treewidth of Proofs}, institution = {Algorithms and Complexity Group, TU Wien}, year = {2017}, number = {AC-TR-17-010}, url = {http://www.ac.tuwien.ac.at/files/tr/ac-tr-17-010.pdf}, }