Tepoyan, L. P., and Daryoush Kalvand. 2010. “NEUMANN PROBLEM FOR FOURTH ORDER DEGENERATE ORDINARY DIFFERENTIAL EQUATIONS”. Proceedings of the YSU A: Physical and Mathematical Sciences 44 (1 (221). Yerevan, Armenia:22-26. https://doi.org/10.46991/PYSU:A/2010.44.1.022.