%0 Journal Article
%T An order-type existence theorem and applications to periodic problems
%A Jifeng Chu and Feng Wang
%J Boundary Value Problems
%D 2013
%I 
%R 10.1186/1687-2770-2013-37
%X Based on the fixed point index and partial order method, one new order-type existence theorem concerning cone expansion and compression is established. As applications, we present sufficient existence conditions for the first and second order periodic problems.
%U http://www.boundaryvalueproblems.com/content/2013/1/37/abstract