Voloshyna, T.V. “An Analogue of Bernside’s Lemma for Finite Inverse Symmetric Semigroup”. Carpathian Mathematical Publications 2, no. 1 (June 30, 2010): 15–23. Accessed April 29, 2024. https://scijournals.pnu.edu.ua/index.php/cmp/article/view/3976.