Bennett, R. J., & Estall, R. C. (1991). Global change and challenge: Geography for the 1990s. Routledge.
Cita Chicago (17th ed.)Bennett, R. J., i Robert C. Estall. Global Change and Challenge: Geography for the 1990s. London: Routledge, 1991.
Cita MLA (9th ed.)Bennett, R. J., i Robert C. Estall. Global Change and Challenge: Geography for the 1990s. Routledge, 1991.
Atenció: Aquestes cites poden no estar 100% correctes.