http://europepmc.org/abstract/MED/25850943
http://europepmc.org/abstract/MED/30181556
http://europepmc.org/abstract/MED/26527317
http://europepmc.org/abstract/MED/24185512
http://europepmc.org/abstract/MED/28270497
http://europepmc.org/abstract/MED/21512767