http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/25159823
http://europepmc.org/abstract/MED/29420467
http://europepmc.org/abstract/MED/22138691
http://europepmc.org/abstract/MED/21248752
http://europepmc.org/abstract/MED/26831717
http://europepmc.org/abstract/MED/20054297
http://europepmc.org/abstract/MED/24487277