http://europepmc.org/abstract/MED/24478380
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/24185509
http://europepmc.org/abstract/MED/22824796
http://europepmc.org/abstract/MED/29360550
http://europepmc.org/abstract/MED/22180306
http://europepmc.org/abstract/MED/24550739
http://europepmc.org/abstract/MED/22503487