Klawitter, Jonathan, and Tamara Mchedlidze. “Upward Planar Drawings With Two Slopes”. Journal of Graph Algorithms and Applications 26, no. 1 (January 1, 2022): 171–198. Accessed July 6, 2024. http://jgaa-v4.cs.brown.edu/index.php/jgaa/article/view/paper587.