(3GdEYQGH GdcGed dBjGJ GdbQBf GdcQje (B/s - (3YHOGdLhGO GdWjHs ((3GdbGgQI (B:s (3ecJHI GdBOGH,s, 1991)
(3GdfU HGddZI GdYQHjIs
Keywords: (3EYQGH GdbQBfs; (3GdTQjYI GdESdGejIs