@article{DE_1993_29_1_a10,
     author = {I. S. Lomov},
     title = {On the basis property of systems of nonregular root vectors of higher-order differential operators},
     journal = {Differencialʹnye uravneni\^a},
     pages = {74--86},
     publisher = {mathdoc},
     volume = {29},
     number = {1},
     year = {1993},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1993_29_1_a10/}
}