http://europepmc.org/abstract/MED/25695693
http://europepmc.org/abstract/MED/8387391
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/11308256
http://europepmc.org/abstract/MED/26289771
http://europepmc.org/abstract/MED/15710230
http://europepmc.org/abstract/MED/8306343