http://europepmc.org/abstract/MED/26744134
http://europepmc.org/abstract/MED/26214590
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/28356599
http://europepmc.org/abstract/MED/22842228
http://europepmc.org/abstract/MED/22817889
http://europepmc.org/abstract/MED/23171796