Knowles, R. (1981). Economic and Social Geography (Fourth Edition). ELSEVIER.
Cita Chicago (17th ed.)Knowles, R. Economic and Social Geography (Fourth Edition). ELSEVIER, 1981.
Cita MLA (8th ed.)Knowles, R. Economic and Social Geography (Fourth Edition). ELSEVIER, 1981.
Atenció: Aquestes cites poden no estar 100% correctes.