Isgur, Abraham, Vitaly Kuznetsov, Mustazee Rahman, and Stephen Tanny. “Nested Recursions, Simultaneous Parameters and Tree Superpositions”. The Electronic Journal of Combinatorics 21, no. 1 (March 10, 2014): P1.49. Accessed April 3, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v21i1p49.