http://europepmc.org/abstract/MED/22323480
http://europepmc.org/abstract/MED/25516983
http://europepmc.org/abstract/MED/27029036
http://europepmc.org/abstract/MED/23280334
http://europepmc.org/abstract/MED/24854193
http://europepmc.org/abstract/MED/24030381