DerechV. D. “Classification of Finite Commutative Semigroups for Which the Inverse Monoid of Local Automorphisms Is a ∆-Semigroup”. Ukrains’kyi Matematychnyi Zhurnal 67, no. 7 (July 25, 2015): 867-873. Accessed December 4, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/2029.