Flavell, J. H. (1985). Cognitive development (2nd.ed.). Prentice - Hall.
Dyfyniad Arddull ChicagoFlavell, John H. Cognitive Development. 2nd.ed. New Jersey: Prentice - Hall, 1985.
Dyfyniad MLAFlavell, John H. Cognitive Development. 2nd.ed. Prentice - Hall, 1985.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.