Vallen, G. K., Vallen, J. J., & Robinson, G. F. (2008). Check-in check-out (2nd Canadian ed.). Pearson Education.
Cita Chicago Style (17a ed.)Vallen, Gary K., Jerome J. Vallen, y Gary F. Robinson. Check-in Check-out. 2nd Canadian ed. Toronto, Ontario: Pearson Education, 2008.
Cita MLA (9a ed.)Vallen, Gary K., et al. Check-in Check-out. 2nd Canadian ed. Pearson Education, 2008.
Precaución: Estas citas no son 100% exactas.