Lotfikar, R. “METHOD OF GALYORKIN FOR NONLINEAR SOBOLEV TYPE EQUATIONS”. Proceedings of the YSU A: Physical and Mathematical Sciences 42, no. 3 (217) (October 6, 2023): 10–15. Accessed July 22, 2024. https://journals.ysu.am/index.php/proceedings-phys-math/article/view/vol42_no3_2008_p010-015.