http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/22722201
http://europepmc.org/abstract/MED/26249178
http://europepmc.org/abstract/MED/16959974
http://europepmc.org/abstract/MED/28921573
http://europepmc.org/abstract/MED/22608084