@article{DE_1990_26_11_a15,
     author = {M. K. Bugir},
     title = {Oscillation of solutions of linear differential equations in spaces of constant curvature},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1956--1961},
     publisher = {mathdoc},
     volume = {26},
     number = {11},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1990_26_11_a15/}
}