http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/23441165
http://europepmc.org/abstract/MED/9115587
http://europepmc.org/abstract/MED/1346255
http://europepmc.org/abstract/MED/24868540
http://europepmc.org/abstract/MED/9284834
http://europepmc.org/abstract/MED/22089350
http://europepmc.org/abstract/MED/22286061