APA (7th ed.) Zitazioa
Duggal, K. N. (2002). Elements of environmental engineering (6th ed.). S. Chand.
Chicago Style (17th ed.) Zitazioa
Duggal, K. N. Elements of Environmental Engineering. 6th ed. New Delhi: S. Chand, 2002.
MLA (9th ed.) Zitazioa
Duggal, K. N. Elements of Environmental Engineering. 6th ed. S. Chand, 2002.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.