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