http://europepmc.org/abstract/MED/22975805
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/28776576
http://europepmc.org/abstract/MED/18948947
http://europepmc.org/abstract/MED/2197591
http://europepmc.org/abstract/MED/22980975