http://europepmc.org/abstract/MED/12144684
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/21556517
http://europepmc.org/abstract/MED/14976538
http://europepmc.org/abstract/MED/1913680
http://europepmc.org/abstract/MED/8473053