Harutunyan, T. N., and G. H. Sahakyan. “THE EXISTENCE OF THE EIGENVALUES FOR DIRAC’S TWO- PARAMETER BOUNDARY-VALUE PROBLEM”. Proceedings of the YSU A: Physical and Mathematical Sciences 40, no. 2 (210) (May 30, 2006): 25–40. Accessed November 23, 2024. https://pub.ysu.am/index.php/proceedings-phys-math/article/view/vol40_no2_2006_pp025-040.