http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/27135926
http://europepmc.org/abstract/MED/22722201
http://europepmc.org/abstract/MED/21995386
http://europepmc.org/abstract/MED/28921573
http://europepmc.org/abstract/MED/17932254