@article{SM_1967_3_3_a2,
     author = {L. P. Shilnikov},
     title = {On a {Poincare--Birkhoff} problem},
     journal = {Sbornik. Mathematics},
     pages = {353--371},
     publisher = {mathdoc},
     volume = {3},
     number = {3},
     year = {1967},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1967_3_3_a2/}
}