@article{DE_1971_7_5_a13,
     author = {V. F. Butuzov},
     title = {A certain integro-differential equation with a small parameter multiplying the derivative in the case when the degenerate equation occurs in the spectrum},
     journal = {Differencialʹnye uravneni\^a},
     pages = {919--922},
     publisher = {mathdoc},
     volume = {7},
     number = {5},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1971_7_5_a13/}
}