Hancock, P. L., & Skinner, B. J. (2000). Oxford companion to the Earth. Oxford University Press.
Dyfyniad Arddull ChicagoHancock, Paul Land, and Brian J. Skinner. Oxford Companion to the Earth. Oxford: Oxford University Press, 2000.
Dyfyniad MLAHancock, Paul Land, and Brian J. Skinner. Oxford Companion to the Earth. Oxford University Press, 2000.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.