Remarks on a mixed boundary-value problem for linear hyperbolic partial differential equations in two independent variables

Aziz, A. K., & J. B. Diaz, On a mixed boundary value problem for linear hyperbolic partial differential equations in two independent variables. Arch. Rational Mech. Anal. 10, 1–28 (1962). Aziz, A. K., On hyperbolic partial differential equations in several independent variables. To appear in Duke Math. J. Aziz, A. K., & W. Bogdanowicz, On a generalized Goursat problem for nonlinear hyperbolic partial differential equations. Submitted to Contributions to Differential Equations. Kamke, E., Differentialgleichungen reeller Funktionen, pp. 412–415, Chelsea. New York 1947.