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http://europepmc.org/abstract/MED/10083732
http://europepmc.org/abstract/MED/11114633
http://europepmc.org/abstract/MED/15273715
http://europepmc.org/abstract/MED/7565764
http://europepmc.org/abstract/MED/10074915
http://europepmc.org/abstract/MED/11216646
http://europepmc.org/abstract/MED/10646882
http://europepmc.org/abstract/MED/8740514