Παραπομπή σε μορφή APA (7η εκδ.)

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

Παραπομπή σε μορφή Chicago (17η εκδ.)

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

Παραπομπή σε μορφή MLA (9th εκδ.)

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