С.А. Щёголев. 2023. “On the Reduction of the Linear System of the Differential Equations to the Bi-Diagonal Kind”. BULLETIN OF THE L.N. GUMILYOV EURASIAN NATIONAL UNIVERSITY. Mathematics. Computer Science. Mechanics Series 128 (3):34-45. https://bulmathmc.enu.kz/index.php/main/article/view/52.