http://europepmc.org/abstract/MED/8938142
http://europepmc.org/abstract/MED/7882351
http://europepmc.org/abstract/MED/26168399
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/9624535
http://europepmc.org/abstract/MED/7563154
http://europepmc.org/abstract/MED/9673367