APA
World Health Organization, . (2006). WHO guidelines for the safe use of wastewater, excreta and greywater. Geneva, SW: WHO.
Chicago
World Health Organization, . 2006. WHO guidelines for the safe use of wastewater, excreta and greywater. Geneva, SW: WHO.
Harvard
World Health Organization, . (2006). WHO guidelines for the safe use of wastewater, excreta and greywater. Geneva, SW: WHO.
MLA
World Health Organization, . WHO guidelines for the safe use of wastewater, excreta and greywater. Geneva, SW: WHO. 2006.