Martin, Ryan, and Brendon Stanton. “Lower Bounds for Identifying Codes in Some Infinite Grids”. The Electronic Journal of Combinatorics 17, no. 1 (September 13, 2010): R122. Accessed March 14, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v17i1r122.