http://europepmc.org/abstract/MED/25148578
http://europepmc.org/abstract/MED/15133491
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/24265153
http://europepmc.org/abstract/MED/23890154
http://europepmc.org/abstract/MED/25886620