http://europepmc.org/abstract/MED/8187092
http://europepmc.org/abstract/MED/11753042
http://europepmc.org/abstract/MED/20668451
http://europepmc.org/abstract/MED/12114798
http://europepmc.org/abstract/MED/1630814
http://europepmc.org/abstract/MED/8137263
http://europepmc.org/abstract/MED/8513440