@article{ND_2015_11_2_a9,
     author = {A. P. Markeev},
     title = {On the {Birkhoff} transformation in the case of complete degeneracy of the quadratic part of the {Hamiltonian}},
     journal = {Russian journal of nonlinear dynamics},
     pages = {343--352},
     publisher = {mathdoc},
     volume = {11},
     number = {2},
     year = {2015},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ND_2015_11_2_a9/}
}