Hosseiny Matikolai, S.A. “ON THE ANISOTROPIC BOUNDARY VALUE PROBLEM, CONNECTED WITH HELMHOLTZE-SCHRÖDINGER ЕQUATION, UNDER THE BOUNDARY CONDITIONS OF THE FIRST AND SECOND TYPE”. Proceedings of the YSU A: Physical and Mathematical Sciences, vol. 45, no. 1 (224), Feb. 2011, pp. 7-11, doi:10.46991/PYSU:A/2011.45.1.007.