National Retail Federation (2007), “National Retail Federation 4-5-4 Calendar,” http://www.nrf.com/.

Technical Committee ISO/TC 154 (Processes, Data Elements, and Documents in Commerce, Industry, and Administration) (2004), ISO 8601:2004 Data Elements and Interchange Formats—Information Interchange—Representation of Dates and Times, 3rd ed., Technical report, International Organization for Standardization.