@article{IM_1992__110_2_144039,
     author = {David E. Barrett and Jeffrey Diller},
     title = {Poincar\'e series and holomorphic averaging.},
     journal = {Inventiones mathematicae},
     pages = {23--28},
     publisher = {mathdoc},
     volume = {110},
     number = {2},
     year = {1992},
     zbl = {0769.30036},
     url = {http://geodesic.mathdoc.fr/item/IM_1992__110_2_144039/}
}