http://europepmc.org/abstract/MED/24140581
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/29683790
http://europepmc.org/abstract/MED/28805995
http://europepmc.org/abstract/MED/24285547
http://europepmc.org/abstract/MED/25257301