1. Maple V Language Reference Manual;Char,1991
2. On averaging, reduction and symmetry in Hamiltonian systems;Churchill;J. Differential Equations,1983
3. On water waves as a Hamiltonian system;Craig,1987
4. Normal forms for water waves;Craig,1994
5. W. Craig, S.B. Kuksin and C.E. Wayne (1994), manuscript in preparation.