@article{DAN_1972_203_1_a3,
     author = {N. B. Engibaryan},
     title = {On the factorization of symmetric integral operators},
     journal = {Doklady Akademii Nauk},
     pages = {19--21},
     publisher = {mathdoc},
     volume = {203},
     number = {1},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1972_203_1_a3/}
}