@article{CRMATH_2006__343_10_657_0,
     author = {Wang, Duo and Zheng, Min and Peng, Jianping},
     title = {Further reduction of normal forms of formal maps},
     journal = {Comptes Rendus. Math\'ematique},
     pages = {657--660},
     publisher = {Elsevier},
     volume = {343},
     number = {10},
     year = {2006},
     doi = {10.1016/j.crma.2006.10.005},
     language = {en},
     url = {http://www.numdam.org/articles/10.1016/j.crma.2006.10.005/}
}