Moghani, Z. N., M. Mohammadzadeh Karizaki, and M. Khanehgir. “Solutions of Sylvester Equation in $C^*$-Modular Operators”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 73, no. 3, Mar. 2021, pp. 354 -69, doi:10.37863/umzh.v73i3.152.