中国科学院数学与系统科学研究院期刊网
Four Finite Isochronous Centers in a Quartic Z3-equivariant Vector Field
WU Yusen, LIU Yirong
Acta Mathematicae Applicatae Sinica . 2017, (2): 218 -228 .  DOI: 10.12387/C2017020