Christopherson, R. W. (1998). Elemental geosystems (Second Edition.). Prentice Hall.
Dyfyniad Arddull ChicagoChristopherson, Robert W. Elemental Geosystems. Second Edition. New Jersey: Prentice Hall, 1998.
Dyfyniad MLAChristopherson, Robert W. Elemental Geosystems. Second Edition. Prentice Hall, 1998.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.