@article{DAN_1970_192_1_a10,
     author = {B. N. Khimchenko},
     title = {On a theorem of {M.} {V.~Keldysh} and {M.} {A.~Lavrent{\textquoteright}ev}},
     journal = {Doklady Akademii Nauk},
     pages = {46--47},
     year = {1970},
     volume = {192},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1970_192_1_a10/}
}