Bassino, Frédérique, Mathilde Bouvel, and Dominique Rossin. “Enumeration of Pin-Permutations”. The Electronic Journal of Combinatorics 18, no. 1 (March 11, 2011): P57. Accessed March 14, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v18i1p57.