Pei Yu, Maoan Han. Four Limit cycles from perturbing quadratic integrable Systems by quadratic polynomials. I. J. Bifurcation and Chaos, 22(10), 2012. [doi]
@article{YuH12-7,
title = {Four Limit cycles from perturbing quadratic integrable Systems by quadratic polynomials},
author = {Pei Yu and Maoan Han},
year = {2012},
doi = {10.1142/S0218127412502549},
url = {http://dx.doi.org/10.1142/S0218127412502549},
researchr = {https://researchr.org/publication/YuH12-7},
cites = {0},
citedby = {0},
journal = {I. J. Bifurcation and Chaos},
volume = {22},
number = {10},
}