http://europepmc.org/abstract/MED/8473515
http://europepmc.org/abstract/MED/9434876
http://europepmc.org/abstract/MED/23907151
http://europepmc.org/abstract/MED/1737400
http://europepmc.org/abstract/MED/28634282
http://europepmc.org/abstract/MED/8630516