http://europepmc.org/abstract/MED/11238048
http://europepmc.org/abstract/MED/23554536
http://europepmc.org/abstract/MED/23208952
http://europepmc.org/abstract/MED/12414520
http://europepmc.org/abstract/MED/11956818
http://europepmc.org/abstract/MED/24969024
http://europepmc.org/abstract/MED/26421956