http://europepmc.org/abstract/MED/29681454
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/21280140
http://europepmc.org/abstract/MED/18386774
http://europepmc.org/abstract/MED/22510280
http://europepmc.org/abstract/MED/22980975