@article{ND_2007_3_4_a4,
     author = {S. V. Gonchenko and A. S. Gonchenko},
     title = {Towards a classification of linear and nonlinear smale horseshoes},
     journal = {Russian journal of nonlinear dynamics},
     pages = {423--443},
     publisher = {mathdoc},
     volume = {3},
     number = {4},
     year = {2007},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ND_2007_3_4_a4/}
}