We consider the Lotka-Volterra system as a Hamiltonian one and study a special perturbation of it. For this perturbed system we get results on the number of limit cycles. The main tools used are Abelian integrals and degenerate Hopf bifurcation. © 1996 Academic Press, Inc.
Gasull, A., Guillamon, A., Li, C., & Zhang, Z. (1996). Study of perturbed Lotka-Volterra systems via Abelian integrals. Journal of Mathematical Analysis and Applications, 198, 703-728. https://doi.org/10.1006/jmaa.1996.0109