Vougalter, Vitali. “Solvability Conditions for Some Systems of Nonlinear Non-Fredholm Elliptic Equations”. Discontinuity, Nonlinearity, and Complexity 2, no. 2 (August 17, 2026): 159–165. Accessed August 17, 2026. https://lhscientificpublishing.com/index.php/DNC/article/view/2072.