@article{DE_1986_22_8_a8,
     author = {M. Rakhimov},
     title = {Exact bounds on a closed interval for eigen- and associated functions of a quadratic pencil of second-order ordinary nonselfadjoint differential operators},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1374--1386},
     publisher = {mathdoc},
     volume = {22},
     number = {8},
     year = {1986},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1986_22_8_a8/}
}