Electronic Journal of Differential Equations,
Vol. 2001(2001), No. 59, pp. 1-8.

Title: Existence of positive periodic solutions for non-autonomous functional
       differential equations
   
Authors: Sui Sun Cheng (National Tsing Hua Univ., Taiwan)
         Guang Zhang (Yanbei Normal Inst., Datong, China)
          

Abstract:  
  We establish the existence of positive periodic solutions for a
  first-order differential equation with periodic delay. For this
  purpose, we use the fixed point theorem proved by Krasnoselskii.
 
  
Submitted May 16, 2001. Published September 4, 2001.
Math Subject Classifications: 34B15.
Key Words: positive periodic solutions; cone; delay.