É. M. Zhmud, “On the multiplier of a group with nontrivial center”, Ukr. Mat. Zhurn., vol. 47, no. 4, pp. 546–550, Apr. 1995, Accessed: Apr. 09, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/5455