http://europepmc.org/abstract/MED/23674493
http://europepmc.org/abstract/MED/22271473
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/1913654
http://europepmc.org/abstract/MED/27302833
http://europepmc.org/abstract/MED/29876005
http://europepmc.org/abstract/MED/23199529
http://europepmc.org/abstract/MED/21726664