Gao, Alice L. L., and Sergey Kitaev. “On Partially Ordered Patterns of Length 4 and 5 in Permutations”. The Electronic Journal of Combinatorics 26, no. 3 (August 16, 2019): #P3.26. Accessed June 3, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v26i3p26.