@article{MAT_1974_18_2_a2,
     author = {J. Chazarain and A. Piriou},
     title = {Caract\'erisation des probl\`emes mixtes hyperboliques bien pos\'es},
     journal = {Matematika},
     pages = {79--109},
     year = {1974},
     volume = {18},
     number = {2},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MAT_1974_18_2_a2/}
}