Mason, R. S. (1989). Robert Giffen and the Giffen paradox. Philip Allan.
Chicago Style aipamenaMason, Roger S. Robert Giffen and the Giffen Paradox. Oxford: Philip Allan, 1989.
MLA aipamenaMason, Roger S. Robert Giffen and the Giffen Paradox. Philip Allan, 1989.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.