O'Sullivan, P. (1981). Geographical economics. New York: Wiley.
Dyfyniad Arddull ChicagoO'Sullivan, Patrick. Geographical Economics. New York: Wiley, 1981.
Dyfyniad MLAO'Sullivan, Patrick. Geographical Economics. New York: Wiley, 1981.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.