Clark, C., & Haswell, M. R. (1966). The economics of subsistence agriculture (2d ed.). Macmillan.
Dyfyniad Arddull ChicagoClark, Colin, and Margaret Rosary Haswell. The Economics of Subsistence Agriculture. 2d ed. London: Macmillan, 1966.
Dyfyniad MLAClark, Colin, and Margaret Rosary Haswell. The Economics of Subsistence Agriculture. 2d ed. Macmillan, 1966.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.