@article{DAN_1984_276_6_a14,
     author = {V. P. Shapeev},
     title = {Intermediate integrals of a second-order partial differential},
     journal = {Doklady Akademii Nauk},
     pages = {1339--1343},
     publisher = {mathdoc},
     volume = {276},
     number = {6},
     year = {1984},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1984_276_6_a14/}
}