http://europepmc.org/abstract/MED/25957691
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/26071483
http://europepmc.org/abstract/MED/25194673
http://europepmc.org/abstract/MED/25344691
http://europepmc.org/abstract/MED/22810696