1. (Time, 1973). The burger that conquered the country, Time, pp. 84–92.
2. McDonald’s Corporation (Fort Collins Coloradoan (Fort Collins, Colorado), 1977). Ray Kroc, McDonald’s Founder, Fort Collins Coloradoan (Fort Collins, Colorado), p. 16.
3. McDonald’s Corporation (The Naples Daily News (Naples, Florida), 1977). Ray Kroc, McDonald’s Founder, The Naples Daily News (Naples, Florida), p. 4B.
4. Langner, P. (The Boston Globe (Boston, Massachusetts), 1977). 31 billion hamburgers later, The Boston Globe (Boston, Massachusetts), p. 23.
5. Perkins, T. (2023, February 28). Hold the Beef: McDonald’s Avoids the Bold Step It Must Take to Cut Emissions. The Guardian, 10 December 2021. Available online: https://www.theguardian.com/environment/2021/dec/10/mcdonalds-emissions-beef-burgers.