http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/25836323
http://europepmc.org/abstract/MED/26822237
http://europepmc.org/abstract/MED/24151152
http://europepmc.org/abstract/MED/26461232
http://europepmc.org/abstract/MED/22187960
http://europepmc.org/abstract/MED/24332040