Nyboe J, Jensen G, Appleyard M, Schnohr P. "Risk factors for acute myocardial infarction in Copenhagen. I: Hereditary, educational and socioeconomic factors. Copenhagen City Heart Study.". Eur Heart J (10). PMID2598948.
Devereux, G. (2006). ABC of chronic obstructive pulmonary disease. Definition, epidemiology, and risk factors(en inglés)332. British Medical Journal. pp. 1142–1144. PMID16690673..
Centers for Disease Control and Prevention (CDC, Centro de Control e Prevención de Enfermidades) (2002). "Annual smoking-attributable mortality, years of potential life lost, and economic costs--United States, 1995-1999". MMWR Morb. Mortal. Wkly. Rep.51: 3–300. PMID12002168.