http://europepmc.org/abstract/MED/25957691 http://europepmc.org/abstract/MED/29844865 http://europepmc.org/abstract/MED/28481359 http://europepmc.org/abstract/MED/22895193 http://europepmc.org/abstract/MED/25344691 http://europepmc.org/abstract/MED/26109429 http://europepmc.org/abstract/MED/22810696