@article{DE_1980_16_10_a0,
     author = {A. I. Vahabov},
     title = {Conditions for being a basis of eigenelements of differential pencils},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1731--1741},
     publisher = {mathdoc},
     volume = {16},
     number = {10},
     year = {1980},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1980_16_10_a0/}
}