@article{DE_1986_22_12_a4,
     author = {O. A. Veliev},
     title = {Spectral expansion of nonselfadjoint differential operators with periodic coefficients},
     journal = {Differencialʹnye uravneni\^a},
     pages = {2052--2059},
     publisher = {mathdoc},
     volume = {22},
     number = {12},
     year = {1986},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1986_22_12_a4/}
}