中国科学院数学与系统科学研究院期刊网
COMPUTATION FOR ZERO POINT INDEX AND  APPLICATIONS TO SECOND ORDER PERIODIC BOUNDARY VALUE PROBLEM
WANG Feng, SUN Jingxian, CUI Yujun
Journal of Systems Science and Mathematical Sciences . 2011, (8): 975 -984 .  DOI: 10.12341/jssms11681