(3YedjGJ GdHfhc ef GdhLgI GdbGfhfjI (B: s (3OQGSI ddbVGA GdeUQj hGdebGQf hJTQjYGJ GdHdGO GdYQHjI (B: (3JYQja hJfXje GdHfhc (B- (3GdhOGFY GdfbOjI (B- (3GdMSGHGJ GdeUQajI (B- (3GdGYJeGOGJ GdeUQajI (B- (3GdNOeGJ GdeUQajI (B- (3GdVeGfGJ GdebOeI ddHfhc (B- (3eSFhdjI GdHfhc (B/ s - (3YhV, Ydj LeGd GdOjfs ([(3ecGf GdfTQ ZjQ eMOO(B] : s [(3GdfGTQ ZjQ eMOO(B](3, s, 1989)
Keywords: (3GdHfhcs -- (3bhGfjf hJTQjYGJs -- (3eUQs