Willett, W. (1998). Nutritional epidemiology (2nd ed.). Oxford University Press.
Dyfyniad Arddull ChicagoWillett, Walter. Nutritional Epidemiology. 2nd ed. New York: Oxford University Press, 1998.
Dyfyniad MLAWillett, Walter. Nutritional Epidemiology. 2nd ed. Oxford University Press, 1998.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.