"Productivity Growth of the Non-Tradable Sectors in China", by Dong He, Wenlang Zhang, Gaofeng Han and Tommy Wu.

ECONOMIST: Sources and acknowledgments

And although Im Dong-Hyun can barely read the big letters at the top of an optician's chart, he can hit that small, yellow circle time and time again.

BBC: Korea's blind' archer Im Dong-Hyun aims for 2012 gold