http://europepmc.org/abstract/MED/8653691
http://europepmc.org/abstract/MED/8553070
http://europepmc.org/abstract/MED/11040453
http://europepmc.org/abstract/MED/11787853
http://europepmc.org/abstract/MED/25855536
http://europepmc.org/abstract/MED/11248065
http://europepmc.org/abstract/MED/18772397
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/12120000
http://europepmc.org/abstract/MED/23103869
http://europepmc.org/abstract/MED/26378065
http://europepmc.org/abstract/MED/11161385
http://europepmc.org/abstract/MED/11115575
http://europepmc.org/abstract/MED/21412932
http://europepmc.org/abstract/MED/15014009