@article{SM_1974_23_2_a4,
     author = {R. V. Plykin},
     title = {Sources and sinks of $A$-diffeomorphisms of surfaces},
     journal = {Sbornik. Mathematics},
     pages = {233--253},
     publisher = {mathdoc},
     volume = {23},
     number = {2},
     year = {1974},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1974_23_2_a4/}
}