@article{DE_1991_27_5_a11,
     author = {P. P. Zabreiko and L. G. Tret'yakova},
     title = {Periodic solutions of a quasilinear telegraph equation},
     journal = {Differencialʹnye uravneni\^a},
     pages = {815--826},
     year = {1991},
     volume = {27},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1991_27_5_a11/}
}