TEPOYAN, L.P.; GRIGORYAN, H.S. ON DEGENERATE NONSELF-ADJOINT DIFFERENTIAL EQUATIONS OF FOURTH ORDER. Proceedings of the YSU A: Physical and Mathematical Sciences, Yerevan, Armenia, v. 46, n. 3 (229), p. 29–33, 2012. DOI: 10.46991/PYSU:A/2012.46.3.029. Disponível em: https://journals.ysu.am/index.php/proceedings-phys-math/article/view/vol46_no3_2012_pp029-033. Acesso em: 22 jul. 2024.