中国科学院数学与系统科学研究院期刊网
AMS
Numbers of Subnormal Solutions for Higher Order Periodic Differential Equations
Zong Xuan CHEN, Kwang Ho SHON
Acta Mathematica Sinica . 2011, (9): 1753 -1768 .  DOI: 10.1007/s10114-011-8551-y