@article{DE_1968_4_2_a8,
     author = {N. N. Yuberev},
     title = {The preservation of the sign of the {Green's} function of a periodic boundary value problem for a second order difference equation},
     journal = {Differencialʹnye uravneni\^a},
     pages = {269--275},
     publisher = {mathdoc},
     volume = {4},
     number = {2},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1968_4_2_a8/}
}