@article{DAN_1991_321_1_a2,
     author = {P. A. Mishnaevskii and A. G. Ramm},
     title = {A uniqueness theorem for a problem of {Goursat--Darboux} type},
     journal = {Doklady Akademii Nauk},
     pages = {19--22},
     publisher = {mathdoc},
     volume = {321},
     number = {1},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1991_321_1_a2/}
}