Bihun, Y., R. Petryshyn, I. Skutar, and H. Melhyk. “Multifrequency System With Multipoint and Integral Conditions”. Acta Et Commentationes Exact and Natural Sciences, Vol. 12, no. 2, Feb. 2022, pp. 19-32, doi:10.36120/2587-3644.v12i2.19-32.