http://europepmc.org/abstract/MED/24816253
http://europepmc.org/abstract/MED/11756228
http://europepmc.org/abstract/MED/11163116
http://europepmc.org/abstract/MED/25656989
http://europepmc.org/abstract/MED/22484628
http://europepmc.org/abstract/MED/23196062
http://europepmc.org/abstract/MED/10485468
http://europepmc.org/abstract/MED/12067995