@article{IM2_1975_9_3_a4,
     author = {M. Kh. Gizatullin and V. I. Danilov},
     title = {Automorphisms of affine {surfaces.~I}},
     journal = {Izvestiya. Mathematics },
     pages = {493--534},
     publisher = {mathdoc},
     volume = {9},
     number = {3},
     year = {1975},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1975_9_3_a4/}
}