http://europepmc.org/abstract/MED/29072370
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/28218421
http://europepmc.org/abstract/MED/27022117
http://europepmc.org/abstract/MED/25344691
http://europepmc.org/abstract/MED/22810696