中国科学院数学与系统科学研究院期刊网
The Number of Zeros of Abelian Integrals for Near-Hamilton System of Degree Three with a Butterfly
Ji Hua YANG, Er Li ZHANG, San Jie LI, Mei LIU
Acta Mathematica Sinica, Chinese Series . 2018, (1): 19 -26 .  DOI: 10.12386/A2018sxxb0002