http://europepmc.org/abstract/MED/9288106
http://europepmc.org/abstract/MED/12697903
http://europepmc.org/abstract/MED/23960188
http://europepmc.org/abstract/MED/28302137
http://europepmc.org/abstract/MED/29386642
http://europepmc.org/abstract/MED/12149228