Aval, Jean-Christophe, and Philippe Duchon. “Enumeration of Alternating Sign Matrices of Even Size (Quasi-)Invariant under a Quarter-Turn Rotation”. The Electronic Journal of Combinatorics 17, no. 1 (March 29, 2010): R51. Accessed March 27, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v17i1r51.