(3QSGFd GdaGQhb YeQ Hf GdNWGH (B((3QV(B)(3Gdi cGaI GdGeUGQ GdGSdGejI GdTGe (B.(3GdYQGb(B.(3GdGQOf (B.(3adSWjf (B.(3Gdjef(B.(3GjQGf(B:s - (3GdLHhQj ,YHO GddWja GSeGYjd YjSi s ((3O(B.(3e(B:s (3GdTQcI GdYQGbjI ddWHGYI GdafjI GdeMOOI ,s, 1990)
Keywords: (3GdJGQjN GdGSdGej s