Duggal, K. (1996). Elements of environmental engineering (6th ed.). S.Chand & Co.
Dyfyniad Arddull ChicagoDuggal, K.N. Elements of Environmental Engineering. 6th ed. New Delhi: S.Chand & Co, 1996.
Dyfyniad MLADuggal, K.N. Elements of Environmental Engineering. 6th ed. S.Chand & Co, 1996.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.