He, Jinhua, Louis A. Valentin, Xiaoyan Yin, and Gexin Yu. “Extremal Permutations in Routing Cycles”. The Electronic Journal of Combinatorics 23, no. 3 (September 16, 2016): P3.47. Accessed April 3, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v23i3p47.