http://europepmc.org/abstract/MED/27284958
http://europepmc.org/abstract/MED/30181556
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/22009941
http://europepmc.org/abstract/MED/27245685
http://europepmc.org/abstract/MED/22722201
http://europepmc.org/abstract/MED/22249247
http://europepmc.org/abstract/MED/21892209