http://europepmc.org/abstract/MED/23856246
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/24504440
http://europepmc.org/abstract/MED/26831717
http://europepmc.org/abstract/MED/20054297
http://europepmc.org/abstract/MED/23797736