中国科学院数学与系统科学研究院期刊网
AMS
Elementary Bifurcations of Non-Critical but Non-Hyperbolic Invariant Tori
Jian Hua SUN
Acta Mathematica Sinica . 2003, (1): 159 -170 .  DOI: 10.1007/s10114-002-0213-7