APA
World Health Organization, . (1988). Vitamin a supplements: a guide to their use in the treatment and prevention of vitamin a deficiency and xerophthalia : prepared by WHO / iNicef / ivacg task force. Geneva: World Health Oraganization.
Chicago
World Health Organization, . 1988. Vitamin a supplements: a guide to their use in the treatment and prevention of vitamin a deficiency and xerophthalia : prepared by WHO / iNicef / ivacg task force. Geneva: World Health Oraganization.
Harvard
World Health Organization, . (1988). Vitamin a supplements: a guide to their use in the treatment and prevention of vitamin a deficiency and xerophthalia : prepared by WHO / iNicef / ivacg task force. Geneva: World Health Oraganization.
MLA
World Health Organization, . Vitamin a supplements: a guide to their use in the treatment and prevention of vitamin a deficiency and xerophthalia : prepared by WHO / iNicef / ivacg task force. Geneva: World Health Oraganization. 1988.