Thanatipanonda, Thotsaporn "Aek". “Further Hopping With Toads and Frogs”. The Electronic Journal of Combinatorics 18, no. 1 (March 24, 2011): P67. Accessed March 17, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v18i1p67.