Jelínková, Eva, Jan Kára, Jan Kratochvíl, Martin Pergel, Ondřej Suchý, and Tomáš Vyskocil. “Clustered Planarity: Small Clusters in Cycles and Eulerian Graphs”. Journal of Graph Algorithms and Applications 13, no. 3 (November 1, 2009): 379–422. Accessed January 18, 2025. https://jgaa-v4.cs.brown.edu/index.php/jgaa/article/view/paper192.