@article{IVM_1987_9_a7,
     author = {S. G. Kreǐn and S. Ya. L'vin},
     title = {Overdetermined and underdetermined equations in {Hilbert} spaces},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {59--66},
     publisher = {mathdoc},
     number = {9},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1987_9_a7/}
}