Harutunyan, T. N.; Sahakyan, G. H. THE EXISTENCE OF THE EIGENVALUES FOR DIRAC’S TWO- PARAMETER BOUNDARY-VALUE PROBLEM. Proc. YSU A: Phys. Math. Sci. 2006, 40 (2 (210), 25-40. https://doi.org/10.46991/PYSUA.2007.41.2.025.