http://europepmc.org/abstract/MED/24816253
http://europepmc.org/abstract/MED/22484628
http://europepmc.org/abstract/MED/11895856
http://europepmc.org/abstract/MED/7606196
http://europepmc.org/abstract/MED/8940997
http://europepmc.org/abstract/MED/9886570
http://europepmc.org/abstract/MED/23196062
http://europepmc.org/abstract/MED/7633655
http://europepmc.org/abstract/MED/11376803