APA
World Health Organization, . (1980). World health organization expanded programme on immunization. Geneva: WHO.
Chicago
World Health Organization, . 1980. World health organization expanded programme on immunization. Geneva: WHO.
Harvard
World Health Organization, . (1980). World health organization expanded programme on immunization. Geneva: WHO.
MLA
World Health Organization, . World health organization expanded programme on immunization. Geneva: WHO. 1980.