http://europepmc.org/abstract/MED/16575012
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/27107065
http://europepmc.org/abstract/MED/23525077
http://europepmc.org/abstract/MED/23158210
http://europepmc.org/abstract/MED/20840671
http://europepmc.org/abstract/MED/14724583