Mchedlidze, Tamara, and Antonios Symvonis. “Crossing-Optimal Acyclic HP-Completion for Outerplanar St-Digraphs”. Journal of Graph Algorithms and Applications 15, no. 3 (July 1, 2011): 373–415. Accessed December 22, 2024. https://jgaa.info/index.php/jgaa/article/view/paper231.