World Health Organization (November 2011). "Meningococcal vaccines : WHO position paper, November 2011". Wkly. Epidemiol. Rec. 86 (47): 521–540. hdl:10665/241846. PMID22128384.
World Health Organization (November 2011). "Meningococcal vaccines : WHO position paper, November 2011". Wkly. Epidemiol. Rec. 86 (47): 521–540. hdl:10665/241846. PMID22128384.