Vallen, G. K., & Vallen, J. J. (2013). Check-in check-out (Ninth edition.). Pearson.
Chicago Style aipamenaVallen, Gary K., and Jerome J. Vallen. Check-in Check-out. Ninth edition. Boston: Pearson, 2013.
MLA aipamenaVallen, Gary K., and Jerome J. Vallen. Check-in Check-out. Ninth edition. Pearson, 2013.
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