(2002). Vacines and Biologicals Who vaccine preventable diasease monitoring system 2002 global summary.
Chicago-viite (17. p.)Vacines and Biologicals Who Vaccine Preventable Diasease Monitoring System 2002 Global Summary. 2002.
MLA-viite (9. p.)Vacines and Biologicals Who Vaccine Preventable Diasease Monitoring System 2002 Global Summary. 2002.
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