@article{MAN_1926__95_159150,
     author = {J.F. Ritt},
     title = {Transcendental transcendency of certain functions of {Poincar\'e}},
     journal = {Mathematische Annalen},
     pages = {671--682},
     publisher = {mathdoc},
     volume = {95},
     year = {1926},
     zbl = {52.0321.04},
     url = {http://geodesic.mathdoc.fr/item/MAN_1926__95_159150/}
}