Chuchman, I.Ya., and O.V. Gutik. “Topological Monoids of Almost Monotone Injective Co-Finite Partial Selfmaps of the Set of Positive Integers”. Carpathian Mathematical Publications, vol. 2, no. 1, June 2010, pp. 119-32, https://journals.pnu.edu.ua/index.php/cmp/article/view/3998.