Cita APA (7th ed.)
Duggal, K. N. (2002). Elements of environmental engineering (6th ed.). S. Chand.
Cita Chicago (17th ed.)
Duggal, K. N. Elements of Environmental Engineering. 6th ed. New Delhi: S. Chand, 2002.
Cita MLA (9th ed.)
Duggal, K. N. Elements of Environmental Engineering. 6th ed. S. Chand, 2002.
Atenció: Aquestes cites poden no estar 100% correctes.