Brankovic, Ljiljana, Paulette Lieby, and Mirka Miller. “Flattening Antichains With Respect to the Volume”. The Electronic Journal of Combinatorics 6, no. 1 (November 9, 1998): R1. Accessed March 28, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v6i1r1.