@article{DAN_1990_312_2_a18,
     author = {V. I. Zubov},
     title = {The wave equation for an anisotropic medium},
     journal = {Doklady Akademii Nauk},
     pages = {342--345},
     publisher = {mathdoc},
     volume = {312},
     number = {2},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1990_312_2_a18/}
}