中国科学院数学与系统科学研究院期刊网
AMS
Positive Solutions to Singular Boundary Value Problems with Sign Changing Nonlinearities on the Half-Line via Upper and Lower Solutions
Bao Qiang YAN, Donal O'REGAN, Ravi P. AGARWAL
Acta Mathematica Sinica . 2007, (8): 1447 -1456 .  DOI: 10.1007/s10114-005-0822-z