@article{DE_1984_20_9_a9,
     author = {N. Satimov},
     title = {Some generalizations of {L.\,S.~Pontryagin's} square lemma},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1548--1555},
     publisher = {mathdoc},
     volume = {20},
     number = {9},
     year = {1984},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1984_20_9_a9/}
}