1. Advanced Combinatorics;Comtet,1974
2. Nilpotent normal forms and representation theory of sl(2, R);Cushman,1986
3. Splitting algorithm for nilpotent normal forms;Cushman;Dynamics and Stability of Systems,1988
4. Invariant theory and normal form of Hamiltonian vector fields with nilpotent linear parts;Cushman,1987
5. On the normal form of a fully resonant Hamiltonian function;Fekken,1986