(3eMGVQGJ GdehSe GdKbGaj (B: s $1 (B/ s ((3CHhXHj (B: s (3OGQ GdeJfHj ddWHGYI hGdfTQ $1 (B1988 (3, s, 1989)
Keywords: (3GdKbGaI; GdacQ GdYQHj; GdeMGVQGJs