@article{DE_1989_25_10_a24,
     author = {E. A. Larionov},
     title = {Properties of root functions of some differential operators},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1812--1815},
     publisher = {mathdoc},
     volume = {25},
     number = {10},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1989_25_10_a24/}
}