(3GdZdh hCKQg aj GdEQgGH h EaSGO GdeLJeY (B/ s ([ (3ZjQ eYQa(B];s [(3ZjQ eYQa(B](3,s, 1990)
Keywords: (3OaGY GdeWGYf(B.s; (3GdESdGe(B.s; (3GdcaQ(B.s; (3GdTQcs