Steel, E. W. (1960). Water supply and sewerage (4th ed.). McGraw-Hill.
Dyfyniad Arddull ChicagoSteel, Ernest. W. Water Supply and Sewerage. 4th ed. New York: McGraw-Hill, 1960.
Dyfyniad MLASteel, Ernest. W. Water Supply and Sewerage. 4th ed. McGraw-Hill, 1960.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.