Vallen, G. K., & Vallen, J. J. (2000). Check-in check-out (6th ed.). Upper Saddle River, NJ: Prentice Hall.
Chicago Style aipamenaVallen, Gary K., và Jerome J. Vallen. Check-in Check-out. 6th ed. Upper Saddle River, NJ: Prentice Hall, 2000.
MLA aipamenaVallen, Gary K., và Jerome J. Vallen. Check-in Check-out. 6th ed. Upper Saddle River, NJ: Prentice Hall, 2000.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.