http://europepmc.org/abstract/MED/24136150
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/22187960
http://europepmc.org/abstract/MED/26886166
http://europepmc.org/abstract/MED/26289771
http://europepmc.org/abstract/MED/26428316