http://europepmc.org/abstract/MED/22327622
http://europepmc.org/abstract/MED/26599269
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/20505728
http://europepmc.org/abstract/MED/28088512
http://europepmc.org/abstract/MED/27528220