“…It is a general and powerful method that allows simplification of nonlinear terms of a dynamical system, by distinguishing resonant and nonresonant terms, so that eventually one is able to derive the "skeleton" of the dynamical system containing only the important terms for dynamical behaviors that are responsible for bifurcations and the nature of solutions, in the vicinity of a special solution such as fixed points or periodic orbits [8-10, 16, 17, 21-24]. In the mechanical context, normal form can be used to derive several important analytical results, as well as for showing equivalences with other methods such as NNMs, or appearance of small denominators in perturbative schemes, hence making it a cornerstone of all perturbation techniques [14,15,25,26]. The computation technique for deriving normal forms and coefficients of the associated nonlinear change of coordinates can be efficiently automatized by using symbolic computational toolboxes, as shown, for example, in [18,19].…”