http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/9624535
http://europepmc.org/abstract/MED/27588476
http://europepmc.org/abstract/MED/25567908
http://europepmc.org/abstract/MED/27105513
http://europepmc.org/abstract/MED/9816274
http://europepmc.org/abstract/MED/22980975