http://europepmc.org/abstract/MED/9270015
http://europepmc.org/abstract/MED/17266182
http://europepmc.org/abstract/MED/17350822
http://europepmc.org/abstract/MED/8895490
http://europepmc.org/abstract/MED/1655254
http://europepmc.org/abstract/MED/10564952
http://europepmc.org/abstract/MED/1672732
http://europepmc.org/abstract/MED/7903205
http://europepmc.org/abstract/MED/21822264
http://europepmc.org/abstract/MED/11191353
http://europepmc.org/abstract/MED/10662591
http://europepmc.org/abstract/MED/23788652
http://europepmc.org/abstract/MED/8290606
http://europepmc.org/abstract/MED/25021421
http://europepmc.org/abstract/MED/8093350
http://europepmc.org/abstract/MED/11704835
http://europepmc.org/abstract/MED/16078640
http://europepmc.org/abstract/MED/11375957
http://europepmc.org/abstract/MED/15126338
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/12759240
http://europepmc.org/abstract/MED/14499690
http://europepmc.org/abstract/MED/15017592
http://europepmc.org/abstract/MED/8382111