中国科学院数学与系统科学研究院期刊网
Three Symmetric Positive Solutions for Second-order Nonlocal Boundary Value Problems
Yong-ping Sun
Acta Mathematicae Applicatae Sinica(English Series) . 2011, (2): 233 -242 .  DOI: 10.1007/s10255-011-0058-x