BurskiiV. P. “On Boundary-Value Problems for a Second-Order Differential Equation With Complex Coefficients in a Plane Domain”. Ukrains’kyi Matematychnyi Zhurnal 48, no. 11 (November 25, 1996): 1457-1467. Accessed November 24, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/5199.