http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/29420467
http://europepmc.org/abstract/MED/24504440
http://europepmc.org/abstract/MED/22138691
http://europepmc.org/abstract/MED/20054297
http://europepmc.org/abstract/MED/25401301
http://europepmc.org/abstract/MED/23797736