34.U.S. Preventive Services Task Force. Counseling to Prevent Tobacco Use and Tobacco-Related Diseases: Recommendation Statement. November 2003. http://www.uspreventiveservicestaskforce.org/3rduspstf/tobacccoun/tobcounrs.htm
35.James JE. Critical review of dietary caffeine and blood pressure: a relationship that should be taken more seriously. Psychosom Med 2004; 66 (1): 63-71. http://www.ncbi.nlm.nih.gov/pubmed/14747639
36.Sudano I, Flammer AJ, Roas S, Enseleit F, Ruschitzka F, Corti R, Noll G. Cocoa, blood pressure, and vascular function. Curr Hypertens Rep. 2012 Aug;14(4):279-84. http://www.ncbi.nlm.nih.gov/pubmed/22684995