http://europepmc.org/abstract/MED/16271749
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/27159395
http://europepmc.org/abstract/MED/29876005
http://europepmc.org/abstract/MED/22653804
http://europepmc.org/abstract/MED/21470976
http://europepmc.org/abstract/MED/28485815
http://europepmc.org/abstract/MED/22609107