Kochubinska, E., and A. Oliynyk. “Monogenic Free Inverse Semigroups and Partial Automorphisms of Regular Rooted Trees”. Matematychni Studii 61, no. 1 (March 19, 2024): 3-9. Accessed May 13, 2024. http://www.matstud.org.ua/ojs/index.php/matstud/article/view/476.