Czap, Július, and Dávid Hudák. “On Drawings and Decompositions of 1-Planar Graphs”. The Electronic Journal of Combinatorics 20, no. 2 (June 13, 2013): #P54. Accessed April 21, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v20i2p54.