http://europepmc.org/abstract/MED/25957691
http://europepmc.org/abstract/MED/29844865
http://europepmc.org/abstract/MED/24755471
http://europepmc.org/abstract/MED/28465371
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/22895193
http://europepmc.org/abstract/MED/19527492
http://europepmc.org/abstract/MED/27756406