L. Cairo et al., HAMILTONIAN METHOD AND INVARIANT SEARCH FOR 2D QUADRATIC SYSTEMS, Journal of physics. A, mathematical and general, 26(17), 1993, pp. 4371-4386
The Hamiltonian formalism for a two-dimensional system of ODE possessi
ng an invariant of the motion not containing the time explicitly has s
uggested a method for the search of first integrals. Applied to the qu
adratic system it leads to the finding of two phase space configuratio
ns.