@article{DE_1972_8_11_a3,
     author = {I. P. Karklin'},
     title = {Topological equivalence of linear systems of {Pfaffian} equations in neighborhoods of their one-dimensional closed characteristics},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1943--1949},
     publisher = {mathdoc},
     volume = {8},
     number = {11},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1972_8_11_a3/}
}