http://europepmc.org/abstract/MED/24449214
http://europepmc.org/abstract/MED/21720744
http://europepmc.org/abstract/MED/18299449
http://europepmc.org/abstract/MED/22095169
http://europepmc.org/abstract/MED/21880637
http://europepmc.org/abstract/MED/25956045
http://europepmc.org/abstract/MED/20065082
http://europepmc.org/abstract/MED/22075511
http://europepmc.org/abstract/MED/21679311
http://europepmc.org/abstract/MED/19166587