Hakobyan, G.H. “ON A SOLUTIONS OF ONE CLASS OF ALMOST HYPOELLIPTIC EQUATIONS”. Proceedings of the YSU A: Physical and Mathematical Sciences 49, no. 1 (236) (March 16, 2015): 20–25. Accessed November 22, 2024. https://pub.ysu.am/index.php/proceedings-phys-math/article/view/vol49_no1_2015_pp020-025.