http://europepmc.org/abstract/MED/19435942
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/7630644
http://europepmc.org/abstract/MED/8552400
http://europepmc.org/abstract/MED/24695838
http://europepmc.org/abstract/MED/7849711
http://europepmc.org/abstract/MED/7887443
http://europepmc.org/abstract/MED/8674005
http://europepmc.org/abstract/MED/9000591