Further reduction of normal forms of formal maps

Duo Wang; Min Zheng; Jianping Peng

Comptes Rendus. Mathématique, Volume 343 (2006) p. 657-660

Unique normal forms for Hopf-zero vector fields

Guoting Chen; Duo Wang; Jiazhong Yang

Comptes Rendus. Mathématique, Volume 336 (2003) p. 345-348