http://europepmc.org/abstract/MED/10735503
http://europepmc.org/abstract/MED/1793483
http://europepmc.org/abstract/MED/24633157
http://europepmc.org/abstract/MED/9010458
http://europepmc.org/abstract/MED/12211074
http://europepmc.org/abstract/MED/8061177