APA Format
World Health Organization . (2015). Improving nutrition outcomes with better water, sanitation and hygiene : practical solutiuon for policies and programmes. : WHO
MLA Format
World Health Organization . Improving nutrition outcomes with better water, sanitation and hygiene : practical solutiuon for policies and programmes. : WHO, 2015
Australian/Harvard Format
World Health Organization . 2015. Improving nutrition outcomes with better water, sanitation and hygiene : practical solutiuon for policies and programmes. WHO, 
Warning: These citations may not always be 100% accurate.