1. Coupon Savings Report (2016).
https://www.nchmarketing.com/nchpressreleases.aspx
. Accessed 17 Aug 2017
2. Terms and Conditions - Christmas promotion 31 days.
https://app.mcdonalds.es/landing/legal/legal31DiasLocosNavidad.html
. Accessed 17 Aug 2017
3. Kumar, M., Anand, R., Jhingran, A., Mohan, R.: Sales promotions on the Internet. In: Proceedings of the 3rd USENIX Workshop on Electronic Commerce, pp. 167–176, Boston (1998)
4. Jakobsson, M., Mackenzie, P.D., Stern, J.P.: Secure and lightweight advertising on the web. J. Comput. Telecommun. Netw. 31(11), 1101–1109 (1999)
5. Chang, C.C., Wu, C.C., Lin, I.C.: A secure e-coupon system for mobile users. Int. J. Comput. Sci. Netw. Secur. 6(1), 273–280 (2006)