中国科学院数学与系统科学研究院期刊网
Existence of Multiple Positive Solutions of Nonlinear Difference Equatiou
Xiang Yang PENG(1),Hai Tao CAI
Acta Mathematica Sinica, Chinese Series . 2003, (6): 1097 -110 .  DOI: 10.12386/A2003sxxb0146