Author(s): Nguyen Van Hieu (Institute of Physics, NCST of Vietnam)
-- hep-ph/0010154 was replaced with a revised version
on Mon, 23 Oct 2000 07:44:49 GMT (7kb) --
Paper: hep-ph/0010154
Comments: 9 pages,no figure, LaTex, Invited talk given at the International
Conference on Physics at Extreme Energy - Rencontres du Vietnam IV, Hanoi
19-25 July 2000: misprint in the title of the Conference corrected
URL: http://arXiv.org/abs/hep-ph/0010154