中国科学院数学与系统科学研究院期刊网
JCM
On the Mean Absolute Geodesic Curvature of Closed Curves in 2-Dimensional Space Forms
You Ning WANG
Acta Mathematica Sinica . 2003, (4): 757 -764 .  DOI: 10.1007/s10114-002-0237-z