Esperet, Louis, Daniel Gonçalves, and Arnaud Labourel. “Coloring Non-Crossing Strings”. The Electronic Journal of Combinatorics 23, no. 4 (October 14, 2016): P4.4. Accessed March 28, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v23i4p4.