http://europepmc.org/abstract/MED/25957691
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/28978093
http://europepmc.org/abstract/MED/26071483
http://europepmc.org/abstract/MED/19378335
http://europepmc.org/abstract/MED/20544848
http://europepmc.org/abstract/MED/12408524
http://europepmc.org/abstract/MED/25344691