中国科学院数学与系统科学研究院期刊网
AMS
The Study of Minimal Period Estimates for Brake Orbits of Autonomous Subquadratic Hamiltonian Systems
Chong LI
Acta Mathematica Sinica . 2015, (10): 1645 -1658 .  DOI: 10.1007/s10114-015-4421-3