@article{IM2_2011_75_2_a1,
     author = {I. K. Babenko and S. A. Bogatyi},
     title = {The amenability of the substitution group of formal power series},
     journal = {Izvestiya. Mathematics },
     pages = {239--252},
     publisher = {mathdoc},
     volume = {75},
     number = {2},
     year = {2011},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_2011_75_2_a1/}
}