@article{DE_1978_14_4_a15,
     author = {I. D. Avrech},
     title = {Estimates of derivatives with respect to the parameter of the resolvent of a second order differential operator},
     journal = {Differencialʹnye uravneni\^a},
     pages = {719--723},
     publisher = {mathdoc},
     volume = {14},
     number = {4},
     year = {1978},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1978_14_4_a15/}
}