@article{DE_1989_25_1_a20,
     author = {Ya. N. Mamedov},
     title = {On the completeness of root functions of some boundary value problems},
     journal = {Differencialʹnye uravneni\^a},
     pages = {167--169},
     publisher = {mathdoc},
     volume = {25},
     number = {1},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1989_25_1_a20/}
}