2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/80450In this paper, separability of the perturbed two-dimensional isotropic harmonic oscillators with homogeneous polynomial potentials is characterized from their Birkhoff-Gustavson (BG) normalization, one of the conventional methods for non-integrable Hamiltonian systems.15pages, submitted to the Proceedings of the Workshop on Superintegrability in Classical and Quantum Systems. A minor correction is made on eq.(3.9)Exactly Solvable and Integrable Systemstext