{u202A}(3QGVj O(B. (3TMGOI jQhj dce SjQI GdLQGO jMH GdHWjN (B:s {u202A}((3JZQjHI adSWjfjI(B) /s - {u202A}{u200F}(3TMGOI (B:{u(3200F(B} (3QGVi s ((3GdbGgQI (B: s {u202A}{u200F}(3eUQjI ddfTQ h GdJhRjY (B:s, 1990)
Keywords: {u202A}{u200F}(3TMGOI (B:{u(3200F(B} (3QGVi s; (3GdbUU GdYQHjIs; (3GdbUU GdYQHjIs -- (3GdYUQ GdMOjKs; (3GdbUU GdYQHjIs -- (3adSWjfs