http://europepmc.org/abstract/MED/24140581
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/22844452
http://europepmc.org/abstract/MED/24705252
http://europepmc.org/abstract/MED/22821383
http://europepmc.org/abstract/MED/24714777
http://europepmc.org/abstract/MED/15929038
http://europepmc.org/abstract/MED/24880341