MokhonkoA. Z., and MokhonkoA. A. “On Meromorphic Solutions of the Systems of Linear differential equations With Meromorphic Coefficients”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 71, no. 9, Sept. 2019, pp. 1227-40, https://umj.imath.kiev.ua/index.php/umj/article/view/1511.