BarkovskyV. V. “On Green’s Function of a Self-Conjugate Elliptical Operator Generated by a Differential Expression and Inhomogeneous Boundary Value Conditions ”. Ukrains’kyi Matematychnyi Zhurnal 18, no. 2 (March 5, 1966): 84-91. Accessed November 24, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/8718.