中国科学院数学与系统科学研究院期刊网
AMS
The Relation of the Morse Index of Closed Geodesics with the Maslov-type Index of Symplectic Paths
Chun Gen LIU
Acta Mathematica Sinica . 2005, (2): 237 -248 .  DOI: 10.1007/s10114-004-0406-3