(3YHO GdSdGe eMeO YGQa (B:s (3SjQJg (B..(3eMGceJg(B..(3eUQYg(B/s - (3ahRj ,GMeOs ((3HZOGO(B:s (3eWHYI GdOjhGfj ,s, 1989)
Keywords: (3GdYQGb(B-(3JGQjN(B-(3GdYUQ GdMOjK(B-(3YHO GdSdGe YGQas