Bender, Edward A., Zhicheng Gao, and Nicholas C. Wormald. “The Number of Labeled 2-Connected Planar Graphs”. The Electronic Journal of Combinatorics 9, no. 1 (November 10, 2002): R43. Accessed March 15, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v9i1r43.