Asatryan, H. A. “ANALYSIS OF THE POINT SPECTRUM OF THE STURM-LIOUVILLE OPERATOR WITH CERTAIN BEHAVIOR OF POTENTIAL AT INFINITY”. Proceedings of the YSU A: Physical and Mathematical Sciences, vol. 40, no. 1 (209), Mar. 2006, pp. 23-28, doi:10.46991/PYSU:A/2006.40.1.023.