Assanova, A.T. “On the Solvability of Nonlocal Boundary Value Problem for the Systems of Impulsive Hyperbolic Equations With Mixed Derivatives”. Discontinuity, Nonlinearity, and Complexity, vol. 5, no. 2, Aug. 2026, pp. 153-65, https://doi.org/10.5890/DNC.2016.06.005.