http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/9683299
http://europepmc.org/abstract/MED/15161705
http://europepmc.org/abstract/MED/21559688
http://europepmc.org/abstract/MED/8664051
http://europepmc.org/abstract/MED/15564288