@article{EJDE_2014__2014__a95,
     author = {Peng,  Linping and Feng,  Zhaoshen},
     title = {Bifurcation of limit cycles from quartic isochronous systems},
     journal = {Electronic journal of differential equations},
     year = {2014},
     volume = {2014},
     zbl = {1417.34075},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2014__2014__a95/}
}