Ma, Shi-Mei, and Yeong-Nan Yeh. “The Peak Statistics on Simsun Permutations”. The Electronic Journal of Combinatorics 23, no. 2 (April 15, 2016): P2.14. Accessed March 14, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v23i2p14.