Sack, Joshua, and Henning Úlfarsson. “Refined Inversion Statistics on Permutations”. The Electronic Journal of Combinatorics 19, no. 1 (January 27, 2012): P29. Accessed March 27, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v19i1p29.