http://europepmc.org/abstract/MED/11115575
http://europepmc.org/abstract/MED/9788440
http://europepmc.org/abstract/MED/10408907
http://europepmc.org/abstract/MED/26253016
http://europepmc.org/abstract/MED/9892110
http://europepmc.org/abstract/MED/15014009