Albert, Michael, and Mathilde Bouvel. “A General Theory of Wilf-Equivalence for Catalan Structures”. The Electronic Journal of Combinatorics 22, no. 4 (December 23, 2015): P4.45. Accessed March 29, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v22i4p45.