Felsner, Stefan, Gwenaël Joret, Piotr Micek, William T. Trotter, and Veit Wiechert. 2018. “Burling Graphs, Chromatic Number, and Orthogonal Tree-Decompositions”. The Electronic Journal of Combinatorics 25 (1), P1.35. https://doi.org/10.37236/7052.