http://europepmc.org/abstract/MED/26206799
http://europepmc.org/abstract/MED/25595890
http://europepmc.org/abstract/MED/28671688
http://europepmc.org/abstract/MED/22237106
http://europepmc.org/abstract/MED/21828118
http://europepmc.org/abstract/MED/28157215