Cortada, J. W. (2004). The Digital Hand. New York: Oxford University Press.

Erdei, W. M. (1993). Bar Codes: Design, Printing and Quality Control. Mexico: McGraw-Hill Interamerican De Mexico.

Harrell, G. D., Hutt, M. D., & Allen, J. W. (1976). Universal Product Code: Price Removal and Consumer Behavior in Supermarkets. Michigan: Michigan State University.

Lehpamer, H. (2008). Rfid design principles. Massachusetts: Artech House.

Many ways of using QR Codes. Retrieved from

QR Codes: Connecting the Online and Offline Worlds. Retrieved from