http://europepmc.org/abstract/MED/25595892
http://europepmc.org/abstract/MED/23415222
http://europepmc.org/abstract/MED/22158541
http://europepmc.org/abstract/MED/26675346
http://europepmc.org/abstract/MED/24550227
http://europepmc.org/abstract/MED/28771672