Huang, Yuanqiu, Zhangdong Ouyang, and Fengming Dong. “On the Sizes of Bipartite 1-Planar Graphs”. The Electronic Journal of Combinatorics 28, no. 2 (May 21, 2021): P2.22. Accessed March 29, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v28i2p22.