Kabdrakhova, S. S., and O. N. Stanzhytskyi. “Necessary and Sufficient Conditions for the Well-Posed Solvability of a Boundary Value Problem for a Linear Loaded Hyperbolic Equation”. Journal of Mathematics, Mechanics and Computer Science, vol. 112, no. 4, Dec. 2021, doi:10.26577/JMMCS.2021.v112.i4.01.