Bodlaender, Hans, Ton Kloks, Dieter Kratsch, and Haiko Müller. “Treewidth and Minimum Fill-in on D-Trapezoid Graphs”. Journal of Graph Algorithms and Applications 2, no. 5 (January 1, 1998): 1–23. Accessed May 2, 2025. https://www.jgaa.info/index.php/jgaa/article/view/paper8.