1. International Coffee Organisation (2010). Total production of exporting countries. http://www.ico.org
2. T. J. Bond , in Tea, Cocoa and Coffee: Plant Secondary Metabolites and Health, ed. A. Crozier, H. Ashihara and F. Tomâs-Barbéran, Blackwell Publishing, Oxford, 2011, pp. 1–24
3. Association of the Anxiogenic and Alerting Effects of Caffeine with ADORA2A and ADORA1 Polymorphisms and Habitual Level of Caffeine Consumption
4. M. E. J. Lean , H.Ashihara, M. N.Clifford, and A.Crozier, in Tea, Cocoa and Coffee: Plant Secondary Metabolites and Health, ed. A. Crozier, H. Ashihara and F. Tomâs-Barbéran, Blackwell Publishing, Oxford, 2011, pp 25–44
5. Food Standard Agency's advice on caffeine