%0 Journal Article
%T Positive Solutions to Periodic Boundary Value Problems for Four-Order Differential Equations
%A Huantao Zhu
%A Zhiguo Luo
%J ISRN Mathematical Analysis
%D 2012
%I Hindawi Publishing Corporation
%R 10.5402/2012/830983
%U http://dx.doi.org/10.5402/2012/830983