Cita APA (7th ed.)

Okun, D. A., & Ernst, W. R. (1987). Community piped water supply systems in developing countries: A planning manual. World Bank.

Cita Chicago (17th ed.)

Okun, Daniel Alexander, i Walter R. Ernst. Community Piped Water Supply Systems in Developing Countries: A Planning Manual. Washington, D.C: World Bank, 1987.

Cita MLA (9th ed.)

Okun, Daniel Alexander, i Walter R. Ernst. Community Piped Water Supply Systems in Developing Countries: A Planning Manual. World Bank, 1987.