http://europepmc.org/abstract/MED/9047388
http://europepmc.org/abstract/MED/11255261
http://europepmc.org/abstract/MED/10369293
http://europepmc.org/abstract/MED/12118338
http://europepmc.org/abstract/MED/12124774
http://europepmc.org/abstract/MED/9333020
http://europepmc.org/abstract/MED/25149524