@article{MZM_1981_30_2_a4,
     author = {I. V. Aliev and S. Ya. Yakubov},
     title = {Second-order differential-operator equations with discrete spectrum on the whole axis},
     journal = {Matemati\v{c}eskie zametki},
     pages = {187--196},
     publisher = {mathdoc},
     volume = {30},
     number = {2},
     year = {1981},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1981_30_2_a4/}
}