U. S. Environmental Protection Agency. Office of Research and Development. (1979). Process design manual for sludge treatment and disposal. Ohio.
Dyfyniad Arddull ChicagoU. S. Environmental Protection Agency. Office of Research and Development. Process Design Manual for Sludge Treatment and Disposal. Cincinnati: Ohio, 1979.
Dyfyniad MLAU. S. Environmental Protection Agency. Office of Research and Development. Process Design Manual for Sludge Treatment and Disposal. Ohio, 1979.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.