1. L.A. Alexeyeva, Generalized function method in nonstationary boundary value problems for wave equations. Math. J. (Kaz.) 6 (1), 16–32 (2006) (in Russian)
2. L.A. Alexeyeva, Nonstationary boundary value problems for wave equation and their generalized solutions (2007). arXiv:math/0610544 [math.AP]
3. L.A. Alekseyeva, G.K. Zakir’yanova, The Green matrix for strictly hyperbolic systems with second order derivatives. Differ. Equ. 37 (4), 488–494 (2001)
4. L.A. Alekseyeva, G.K. Zakir’yanova, Generalized solutions of initial-boundary value problems for second order hyperbolic systems. J. Comput. Math. Math. Phys. 51 (7), 1280–1293 (2011)
5. G.I. Petrashen, Waves in Anisotropic Media (Leningrag, Nauka, 1978)