http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/18948947
http://europepmc.org/abstract/MED/26164066
http://europepmc.org/abstract/MED/27588476
http://europepmc.org/abstract/MED/25567908
http://europepmc.org/abstract/MED/22980975