Cita APA (7th ed.)
ebrary, Inc, & Sack, R. D. (2002). Progress: Geographical essays. Johns Hopkins University Press.
Cita Chicago (17th ed.)
ebrary, Inc, i Robert David Sack. Progress: Geographical Essays. Baltimore: Johns Hopkins University Press, 2002.
Cita MLA (9th ed.)
ebrary, Inc, i Robert David Sack. Progress: Geographical Essays. Johns Hopkins University Press, 2002.
Atenció: Aquestes cites poden no estar 100% correctes.