(3UdGI GdeUdjf Ydi SjO GdeQSdjf ef GdChdjGA hGdYdeGA hGdYGQajf (B: s (3eY aVd GdUdGI Ydi QShd Gddg Ud Gddg Ydjg hSde (B/ s - (3GdcfL, YHO GdQRGb(B.s ((3MdH (B: s [(3ZjQ eYQa(B](3, s, 1990)
Keywords: (3GdESdGe(B.s; (3GdUdGI Ydi QShd Gddg Udi Gddg Ydjg h Sde(B.s; (3GdCOYjI(B.s