APA
World Health Organization, . (1991). Guidelines for drinking - water quality vol 1 recommendations. CBS Publishers & Distributors Pvt. Ltd., New Delhi: .
Chicago
World Health Organization, . 1991. Guidelines for drinking - water quality vol 1 recommendations. CBS Publishers & Distributors Pvt. Ltd., New Delhi: .
Harvard
World Health Organization, . (1991). Guidelines for drinking - water quality vol 1 recommendations. CBS Publishers & Distributors Pvt. Ltd., New Delhi: .
MLA
World Health Organization, . Guidelines for drinking - water quality vol 1 recommendations. CBS Publishers & Distributors Pvt. Ltd., New Delhi: . 1991.