http://europepmc.org/abstract/MED/11923604
http://europepmc.org/abstract/MED/21458303
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/9823556
http://europepmc.org/abstract/MED/11275993
http://europepmc.org/abstract/MED/11231481