http://europepmc.org/abstract/MED/9628511
http://europepmc.org/abstract/MED/25275298
http://europepmc.org/abstract/MED/10574255
http://europepmc.org/abstract/MED/11255261
http://europepmc.org/abstract/MED/10221335
http://europepmc.org/abstract/MED/25056374
http://europepmc.org/abstract/MED/14586645
http://europepmc.org/abstract/MED/8023167
http://europepmc.org/abstract/MED/7923115