http://europepmc.org/abstract/MED/12460462
http://europepmc.org/abstract/MED/17011185
http://europepmc.org/abstract/MED/24755471
http://europepmc.org/abstract/MED/10416591
http://europepmc.org/abstract/MED/9065402
http://europepmc.org/abstract/MED/11920497
http://europepmc.org/abstract/MED/15154912
http://europepmc.org/abstract/MED/27121310
http://europepmc.org/abstract/MED/20925459
http://europepmc.org/abstract/MED/19378335
http://europepmc.org/abstract/MED/9515795
http://europepmc.org/abstract/MED/17454753
http://europepmc.org/abstract/MED/9591632
http://europepmc.org/abstract/MED/9294210
http://europepmc.org/abstract/MED/9500465
http://europepmc.org/abstract/MED/10493496
http://europepmc.org/abstract/MED/29029407