@article{TM_1985_169_a6,
     author = {L. S. Pontryagin and E. F. Mishchenko},
     title = {Some problems in the theory of differential equations with a~small parameter},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {99--118},
     publisher = {mathdoc},
     volume = {169},
     year = {1985},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_1985_169_a6/}
}