|  |   |       e
 
 
 
  
 
 


" .."
7
1.
2.
.., ..
, 1995 ., 108, . 4, . 1416

3.
.., ..
, 1994 ., 106, . 5, . 1515

4.
5. s=1/2 XY-
6.
.., .., ..
, 2000 ., 118, . 3, . 687

7. s=1/2 XY-