http://europepmc.org/abstract/MED/12101426
http://europepmc.org/abstract/MED/16937357
http://europepmc.org/abstract/MED/19200579
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/11309340
http://europepmc.org/abstract/MED/22183980
http://europepmc.org/abstract/MED/10698519
http://europepmc.org/abstract/MED/19637320
http://europepmc.org/abstract/MED/10754205
http://europepmc.org/abstract/MED/11666046
http://europepmc.org/abstract/MED/9927029
http://europepmc.org/abstract/MED/26822237
http://europepmc.org/abstract/MED/21237236