http://www.pnas.org/content/early/2014/04/03/1323367111.abst...
Here's Ed Yong's reporting on the new one, gives most of the meat and introduces the old one (and criticisms to it): http://phenomena.nationalgeographic.com/2014/04/07/stradivar...
http://www.pnas.org/content/early/2014/04/03/1323367111.abst...