@article{SM_1967_1_2_a3,
     author = {A. F. Leont'ev},
     title = {A uniqueness property},
     journal = {Sbornik. Mathematics},
     pages = {209--220},
     year = {1967},
     volume = {1},
     number = {2},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1967_1_2_a3/}
}