Zhuchok, A. V. and Koppitz, J. (2018) “Free products of $n$-tuple semigroups”, Ukrains’kyi Matematychnyi Zhurnal, 70(11), pp. 1484-1498. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/1652 (Accessed: 25April2024).