@article{DE_1967_3_6_a1,
     author = {S. A. Pak},
     title = {A priori estimate of solutions of boundary value problems for second order ordinary nonlinear differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {890--897},
     publisher = {mathdoc},
     volume = {3},
     number = {6},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1967_3_6_a1/}
}