Submitted on: 15 May 2002.
Revised on: 22 August 2002.
Accepted on: 26 September 2002.
___________________International Journal of Dynamical Systems and Differential Equations
Submitted on: 02 May 2013.
Revised on: 12 June 2013.
Accepted on: 26 June 2013.
___________________International Journal of Dynamical Systems and Differential Equations
Submitted on: 11 June 2007.
Revised on: 05 August 2007.
Accepted on: 30 September 2007.
___________________International Journal of Dynamical Systems and Differential Equations
Submitted on: 28 December 2001.
Revised on: 07 February 2002.
Accepted on: 22 February 2002.
___________________International Journal of Dynamical Systems and Differential Equations
http://reply.papertrans.cn/2/133/13294/13294-15.png
Submitted on: 12 August 1999.
Revised on: 30 October 1999.
Accepted on: 27 December 1999.
___________________International Journal of Dynamical Systems and Differential Equations
Submitted on: 21 May 1999.
Revised on: 30 August 1999.
Accepted on: 16 October 1999.
___________________International Journal of Dynamical Systems and Differential Equations
http://reply.papertrans.cn/2/133/13294/13294-18.png
http://reply.papertrans.cn/2/133/13294/13294-19.png
Submitted on: 12 May 2004.
Revised on: 07 July 2004.
Accepted on: 15 August 2004.
___________________International Journal of Dynamical Systems and Differential Equations