Electronic Journal of Differential Equations,
Vol. 2008(2008), No. 88, pp. 1-11.

Title: Positive periodic solutions for a predator-prey model with
       time delays and impulsive effect
  
Authors: Shan Gao   (Yunnan Univ., China)
         Yongkun Li (Yunnan Univ., China)
 
Abstract: 
 In this article, a two-species predator-prey model with time delays
 and impulsive effect is investigated. By using Mawhin's continuation
 theorem of coincidence degree theory, sufficient conditions are
 obtained for the existence of positive periodic solutions. 
 
Submitted April 7, 2008. Published June 21, 2008.
Math Subject Classifications: 34K13, 34K45, 92D25.
Key Words: Predator-prey model; impulse; positive periodic solution; 
           coincidence degree.