http://europepmc.org/abstract/MED/28915660
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/19228619
http://europepmc.org/abstract/MED/22072542
http://europepmc.org/abstract/MED/20131059
http://europepmc.org/abstract/MED/19554337
http://europepmc.org/abstract/MED/24149775