http://europepmc.org/abstract/MED/10846560
http://europepmc.org/abstract/MED/24388756
http://europepmc.org/abstract/MED/23297126
http://europepmc.org/abstract/MED/9354678
http://europepmc.org/abstract/MED/12217802
http://europepmc.org/abstract/MED/10760686
http://europepmc.org/abstract/MED/17699855
http://europepmc.org/abstract/MED/10956404