Sugden, D. R. (2009). Gray markets: Prevention, detection, and litigation. Oxford University Press.
Chicago Style aipamenaSugden, David R. Gray Markets: Prevention, Detection, and Litigation. Oxford: Oxford University Press, 2009.
MLA aipamenaSugden, David R. Gray Markets: Prevention, Detection, and Litigation. Oxford University Press, 2009.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.