http://europepmc.org/abstract/MED/25595890
http://europepmc.org/abstract/MED/23377281
http://europepmc.org/abstract/MED/22675565
http://europepmc.org/abstract/MED/28671688
http://europepmc.org/abstract/MED/22237106
http://europepmc.org/abstract/MED/28157215
http://europepmc.org/abstract/MED/19494353