@article{DE_1977_13_5_a9,
     author = {S. Yu. Pilyugin},
     title = {Cycles in phase portraits of {Morse--Smale} systems},
     journal = {Differencialʹnye uravneni\^a},
     pages = {874--882},
     publisher = {mathdoc},
     volume = {13},
     number = {5},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1977_13_5_a9/}
}