APA

World Health Organization W., . (1994). Operation and maintenance of urban water supply and sanitation systems : a guide for managers. Ginebra: World Health Organization.

Chicago

World Health Organization Who, . 1994. Operation and maintenance of urban water supply and sanitation systems : a guide for managers. Ginebra: World Health Organization.

Harvard

World Health Organization W., . (1994). Operation and maintenance of urban water supply and sanitation systems : a guide for managers. Ginebra: World Health Organization.

MLA

World Health Organization Who, . Operation and maintenance of urban water supply and sanitation systems : a guide for managers. Ginebra: World Health Organization. 1994.