J Llibre, BD Lopes, JR De Moraes - Qualitative theory of dynamical …, 2014 - Springer
We study the maximum number of limit cycles that bifurcate from the periodic solutions of the
family of isochronous cubic polynomial centers ̇ x= y (-1+ 2 α x+ 2 β x^ 2),\quad ̇ y= x+ α …