Soule, G. (1948). Introduction to economic science. New York: New American Library.
Dyfyniad Arddull ChicagoSoule, George. Introduction to Economic Science. New York: New American Library, 1948.
Dyfyniad MLASoule, George. Introduction to Economic Science. New York: New American Library, 1948.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.