@misc{RM_1997_52_4_a24,
     title = {International {Conference,} dedicated to the 90th anniversary of {L.} {S.~Pontryagin} birth},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     year = {1997},
     volume = {52},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/RM_1997_52_4_a24/}
}