http://europepmc.org/abstract/MED/8272291
http://europepmc.org/abstract/MED/28940304
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/22653804
http://europepmc.org/abstract/MED/25233892
http://europepmc.org/abstract/MED/21168197