@article{DAN_1970_192_1_a9,
     author = {L. S. Frank},
     title = {Coercive boundary value problems for difference operators},
     journal = {Doklady Akademii Nauk},
     pages = {42--45},
     publisher = {mathdoc},
     volume = {192},
     number = {1},
     year = {1970},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1970_192_1_a9/}
}