Erdős, Péter L., Péter Sziklai, and David C. Torney. “A Finite Word Poset”. The Electronic Journal of Combinatorics 8, no. 2 (July 26, 2000): #R8. Accessed April 12, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v8i2r8.