http://europepmc.org/abstract/MED/10850436
http://europepmc.org/abstract/MED/15073856
http://europepmc.org/abstract/MED/23026641
http://europepmc.org/abstract/MED/14654050
http://europepmc.org/abstract/MED/11389059
http://europepmc.org/abstract/MED/22696596
http://europepmc.org/abstract/MED/10423403