中国科学院数学与系统科学研究院期刊网
AMS
On the Existence of Global Bisections of Lie Groupoids
De Shou ZHONG, Zhuo CHEN, Zhang Ju LIU
Acta Mathematica Sinica . 2009, (6): 1001 -1014 .  DOI: 10.1007/s10114-009-6242-8