Resumen de Abelian integrals of quadratic hamiltonian vector fields with an invariant straight line
Chengzhi Li 
, Jaume Llibre , Zhifen Zhang
We prove that the lowest upper bound for the number of isolated zeros of the Abelian integrals associated to quadratic Hamiltonian vector fields having a center and an invariant straight line after quadratic perturbations is one.
