%0 Journal Article
%T Existence of positive solutions for a kind of periodic boundary value problem at resonance
%A Miros awa Zima and Piotr Dryga
%J Boundary Value Problems
%D 2013
%I 
%R 10.1186/1687-2770-2013-19
%X In the paper we provide sufficient conditions for the existence of positive solutions for some second-order differential equation subject to periodic boundary conditions. Our method employs a Leggett-Williams norm-type theorem for coincidences due to O¡¯Regan and Zima. Two examples are given to illustrate the main result of the paper.
%K periodic boundary value problem
%K positive solution
%K coincidence equation
%U http://www.boundaryvalueproblems.com/content/2013/1/19/abstract