@article{SM_2006_197_6_a5,
     author = {Yu. L. Sachkov},
     title = {Complete description of the {Maxwell} strata in the},
     journal = {Sbornik. Mathematics},
     pages = {901--950},
     year = {2006},
     volume = {197},
     number = {6},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2006_197_6_a5/}
}