http://europepmc.org/abstract/MED/8109252
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/29420467
http://europepmc.org/abstract/MED/26895810
http://europepmc.org/abstract/MED/22138691
http://europepmc.org/abstract/MED/26831717