Dzhaliuk N. S. and Petrychkovych V. M. (2021) “Equivalence of matrices in the ring $M(n, R)$ and its subrings”, Ukrains’kyi Matematychnyi Zhurnal, 73(12), pp. 1612 - 1618. doi: 10.37863/umzh.v73i12.6858.