$a (3GdGJMGO GdOhdj dQaY GdGKbGd GdbGfhf GdOhdj hGdbhGYO GdafjI (B/s $b (3hOjY jGSjf GdJcQjJjs - $a (3GdJcQjJj jGSjf hOjY(B.s ($a (3GdYQGb (B{(3LGeYI GdehUd (B}s $c 1984)
Keywords: $a (3GdGJMGO GdOhdj dQaY GdGKbGds -- $x (3GdGKbGds