Meagher, Karen, Lucia Moura, and Brett Stevens. “A Sperner-Type Theorem for Set-Partition Systems”. The Electronic Journal of Combinatorics 12, no. 1 (October 31, 2005): N20. Accessed April 7, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v12i1n20.