http://europepmc.org/abstract/MED/23793026
http://europepmc.org/abstract/MED/29371009
http://europepmc.org/abstract/MED/24927141
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/23313955
http://europepmc.org/abstract/MED/26923342
http://europepmc.org/abstract/MED/23861464