http://europepmc.org/abstract/MED/11179836
http://europepmc.org/abstract/MED/7960232
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/29876005
http://europepmc.org/abstract/MED/22653804
http://europepmc.org/abstract/MED/24071873
http://europepmc.org/abstract/MED/21726664