Patkós, Balázs. “Families That Remain $k$-Sperner Even After Omitting an Element of Their Ground Set”. The Electronic Journal of Combinatorics 20, no. 1 (February 12, 2013): P32. Accessed March 27, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v20i1p32.