http://europepmc.org/abstract/MED/26214590
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/26286987
http://europepmc.org/abstract/MED/22817889
http://europepmc.org/abstract/MED/10070891
http://europepmc.org/abstract/MED/15819981
http://europepmc.org/abstract/MED/16094622