@article{DE_1982_18_12_a3,
     author = {V. A. Il'in and V. V. Tikhomirov},
     title = {The basis property of {Riesz} means of spectral decompositions corresponding to an $n$th-order ordinary nonselfadjoint differential operator},
     journal = {Differencialʹnye uravneni\^a},
     pages = {2098--2126},
     publisher = {mathdoc},
     volume = {18},
     number = {12},
     year = {1982},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1982_18_12_a3/}
}