1. Engholm G, Ferlay J, Christensen N, et al. NORDCAN: Cancer Incidence, Mortality and Prevalence in the Nordic Countries. Version 3.1. Association of Nordic Cancer Registries. Danish Cancer Society; 2008. Available from: http://www.ancr.nu.
2. Faggiano F, Partane T, Kogevinas M, Boffeta P. Socioeconomic differences in cancer incidence and mortality. In: Kogevinas M, Pearce N, Susser M, Boffetta P, editors. Social inequalities and cancer. Lyon: International Agency for Research on Cancer; 1997. p. 65–176.
3. Inequalities in lung cancer mortality by the educational level in 10 European populations;Mackenbach;Eur J Cancer,2004
4. Lung cancer, smoking, and environment: a cohort study of the Danish population;Engholm;BMJ,1996
5. Lung cancer risk and social class. The Copenhagen Male study-17-year follow up;Hein;Dan Med Bull,1992