@article{VUU_2009_1_a2,
     author = {V. Ya. Derr},
     title = {Disconjugacy of solutions of linear differential equations},
     journal = {Vestnik Udmurtskogo universiteta. Matematika, mehanika, kompʹ\^uternye nauki},
     pages = {46--89},
     publisher = {mathdoc},
     number = {1},
     year = {2009},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VUU_2009_1_a2/}
}