@article{CRMATH_2006__342_10_737_0,
     author = {Menous, Fr\'ed\'eric},
     title = {The {Birkhoff} decomposition in groups of formal diffeomorphisms},
     journal = {Comptes Rendus. Math\'ematique},
     pages = {737--740},
     publisher = {Elsevier},
     volume = {342},
     number = {10},
     year = {2006},
     doi = {10.1016/j.crma.2006.02.035},
     language = {en},
     url = {http://www.numdam.org/articles/10.1016/j.crma.2006.02.035/}
}