Currie, James, and Philip Lafrance. “Avoidability Index for Binary Patterns With Reversal”. The Electronic Journal of Combinatorics 23, no. 1 (February 19, 2016): #P1.36. Accessed April 24, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v23i1p36.