@article{UZERU_1991_2_a9,
     author = {H. A. Asatryan and G. Kh. Grlgorlan-Khaktian and A. K. Nikoghosian},
     title = {The wave field in the focus of hyperbolic mirror},
     journal = {Proceedings of the Yerevan State University. Physical and mathematical sciences},
     pages = {74--78},
     publisher = {mathdoc},
     number = {2},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/UZERU_1991_2_a9/}
}