Iranian Mathematical Society (IMS)Bulletin of the Iranian Mathematical Society1017-060X39120130301Existence and uniqueness of solutions for a periodic
boundary value problem165173343ENA.Amini HarandiUniversity of Shahrekord, IranJournal Article20110501In this paper, using the fixed point theory in cone metric spaces, we prove the existence of a unique solution to a first-order ordinary differential equation with periodic boundary conditions in Banach spaces admitting the existence of a lower solution.http://bims.iranjournals.ir/article_343_4afacfa2a4973fe9304d888b866fd3ae.pdf