Medium amplitude limit cycles of some classes of generalized Liénard systems

摘要

Agraïments: Part of the results of this work come from the author’s postdoctoral stay at the Departament de Matemàtiques of the Universitat Autònoma de Barcelona. The author would like to thank the Centre de Recerca Matem`atica for their support and hospitality during the period in which this paper was completed.