http://europepmc.org/abstract/MED/17889709
http://europepmc.org/abstract/MED/12750722
http://europepmc.org/abstract/MED/9207408
http://europepmc.org/abstract/MED/26681761
http://europepmc.org/abstract/MED/7761424
http://europepmc.org/abstract/MED/8982044
http://europepmc.org/abstract/MED/24870754
http://europepmc.org/abstract/MED/21157892
http://europepmc.org/abstract/MED/11091202
http://europepmc.org/abstract/MED/24557455
http://europepmc.org/abstract/MED/7780150
http://europepmc.org/abstract/MED/24910748
http://europepmc.org/abstract/MED/8751464
http://europepmc.org/abstract/MED/15104290
http://europepmc.org/abstract/MED/10774753
http://europepmc.org/abstract/MED/10463610
http://europepmc.org/abstract/MED/9226156
http://europepmc.org/abstract/MED/12621238
http://europepmc.org/abstract/MED/9628428
http://europepmc.org/abstract/MED/18635414
http://europepmc.org/abstract/MED/10049054
http://europepmc.org/abstract/MED/22373549
http://europepmc.org/abstract/MED/9067587