Braunfeld, Samuel. “The Lattice of Definable Equivalence Relations in Homogeneous $n$-Dimensional Permutation Structures”. The Electronic Journal of Combinatorics 23, no. 4 (December 23, 2016): #P4.44. Accessed May 21, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v23i4p44.