http://europepmc.org/abstract/MED/8835820
http://europepmc.org/abstract/MED/8164156
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/2179417
http://europepmc.org/abstract/MED/12879021
http://europepmc.org/abstract/MED/20813562
http://europepmc.org/abstract/MED/2040536
http://europepmc.org/abstract/MED/23408298