Gill, R. T. (1967). Economic development: Past and present. Prentice-Hall.
Dyfyniad Arddull ChicagoGill, Richard T. Economic Development: Past and Present. Englewood Cliffs, NJ: Prentice-Hall, 1967.
Dyfyniad MLAGill, Richard T. Economic Development: Past and Present. Prentice-Hall, 1967.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.