@article{DE_1972_8_3_a5,
     author = {I. I. Kobyakov},
     title = {Conditions for negativity of the {Green's} function of a two-point boundary value problem with deviating argument},
     journal = {Differencialʹnye uravneni\^a},
     pages = {443--452},
     publisher = {mathdoc},
     volume = {8},
     number = {3},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1972_8_3_a5/}
}