1. Abraham, R. & Marsden, J., Foundations of Mechanics, 2nd ed., Benjamin/Cummings, Reading, Mass., 1978.
2. Cushman, R. 1982, Reduction, Brouwer’s Hamiltonian, and the critical inclination, preprint No. 243, University of Utrecht.
3. Deprit, A. 1969, Celest. Mech., 1, 1.
4. Deprit, A. 1982, Celest. Mech., 26, 9.
5. Gordon, W.B. 1969, J. Math. Mech., 19, 111.