1. Inequalities;Beckenbach,1961
2. Some Classes of Partial Differential Equations;Bitsadze,1988
3. Partial Differential Equations;Evans,1998
4. Goursat and Darboux type problems for linear hyperbolic partial differential equations and systems;Kharibegashvili;Mem. Differential Equations Math. Phys.,1995
5. Boundary value problems for some classes of nonlinear wave equations;Kharibegashvili;Mem. Differential Equations Math. Phys.,2009