@article{DAN_1966_167_6_a0,
     author = {M. S. Agranovich},
     title = {Positive mixed problems for certain hyperbolic systems},
     journal = {Doklady Akademii Nauk},
     pages = {1215--1218},
     publisher = {mathdoc},
     volume = {167},
     number = {6},
     year = {1966},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1966_167_6_a0/}
}