@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},
}