http://europepmc.org/abstract/MED/21798893
http://europepmc.org/abstract/MED/8402617
http://europepmc.org/abstract/MED/11325447
http://europepmc.org/abstract/MED/11948487
http://europepmc.org/abstract/MED/12404284
http://europepmc.org/abstract/MED/21798897
http://europepmc.org/abstract/MED/15039212
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/10621852
http://europepmc.org/abstract/MED/12649174
http://europepmc.org/abstract/MED/26619122
http://europepmc.org/abstract/MED/17179101
http://europepmc.org/abstract/MED/28581676
http://europepmc.org/abstract/MED/10779196
http://europepmc.org/abstract/MED/10754498
http://europepmc.org/abstract/MED/9736425
http://europepmc.org/abstract/MED/12771990