Of one over determined system differential equation at private derivative second order with one singular point and one singular line: differential equations. Вест. ПГУ. Мат. Мех. Инф. [Internet]. 2021 Dec. 22 [cited 2026 Sep. 10];(4 (55):14-8. Available from: https://press.psu.ru/index.php/Math/article/view/4964