@article{SM_1987_56_1_a8,
     author = {P. P. Kargaev},
     title = {Nonlocal almost differential operators and interpolation by functions with sparse spectrum},
     journal = {Sbornik. Mathematics},
     pages = {131--140},
     publisher = {mathdoc},
     volume = {56},
     number = {1},
     year = {1987},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1987_56_1_a8/}
}