On second order nonlinear equations with rectilinear characteristics. Gvazava, J. — 2000 Georgian Mathematical Journal
Nonlocal and initial problems for quasilinear nonstrictly hyperbolic equations with general solutions represented by superpositions of arbitrary functions. Gvazava, J. — 2003 Georgian Mathematical Journal
To the theory of boundary value problems for hyperbolic type equations and systems. Gvazava, J.; Kharibegashvili, S. — 1997 Memoirs on Differential Equations and Mathematical Physics