Electronic Journal of Differential Equations,
Vol. 2005(2005), No. 84, pp. 1-8.

Title: Periodic solutions of polynomial non-autonomous 
       differential equations

Author: Mohamad A. M. Alwash (West Los Angeles College, CA, USA)

Abstract: 
 We present some results on the number of periodic solutions for
 scalar non-autonomous polynomial equations of degree five.
 We also consider a class of polynomial equations of any degree.
 Our results give upper bounds for the number of limit cycles of
 two-dimensional systems.
  
Submitted July 7, 2005. Published July 25, 2005.
Math Subject Classifications: 34C25, 34C07, 34C05.
Key Words: Periodic solutions; polynomial non-autonomous equations;
           Abel differential equations; limit cycles; 
	   uniformly isochronous centers; Hilbert's sixteenth problem.