Submitted on: 12 February 2000.
Revised on: 28 April 2000.
Accepted on: 18 June 2000.
___________________INTERNATIONAL JOURNAL OF MODERN PHYSICS C
Submitted on: 01 February 2001.
Revised on: 07 March 2001.
Accepted on: 21 April 2001.
___________________INTERNATIONAL JOURNAL OF MODERN PHYSICS C
Submitted on: 03 March 2003.
Revised on: 24 May 2003.
Accepted on: 19 July 2003.
___________________INTERNATIONAL JOURNAL OF MODERN PHYSICS C
http://reply.papertrans.cn/2/138/13799/13799-34.png
Submitted on: 18 September 1998.
Revised on: 18 October 1998.
Accepted on: 18 November 1998.
___________________INTERNATIONAL JOURNAL OF MODERN PHYSICS C
http://reply.papertrans.cn/2/138/13799/13799-36.png