Paliokas, E. “On Solvability of the Boundary Value Problems for the Multidimensional Elliptic Systems of Partial Equations”. Nonlinear Analysis: Modelling and Control 7, no. 2 (December 5, 2002): 105–112. Accessed April 27, 2024. https://www.journals.vu.lt/nonlinear-analysis/article/view/15196.