We characterize the centers of the quasi-homogeneous planar polynomial differential systems of degree three. Such systems do not admit isochronous centers. At most one limit cycle can bifurcate from the periodic orbits of a center of a cubic homogeneous polynomial system using the averaging theory of first order
Aziz, W.; Llibre, J.; Pantazi, C. Centers of quasi-homogeneous polynomial differential equations of degree three. "Advances in mathematics", 20 Març 2014, vol. 254, p. 233-250.