http://europepmc.org/abstract/MED/27630302
http://europepmc.org/abstract/MED/24140581
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/23441165
http://europepmc.org/abstract/MED/24695838
http://europepmc.org/abstract/MED/26919320
http://europepmc.org/abstract/MED/23917401
http://europepmc.org/abstract/MED/15517309