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1 American Cancer Society. Cancer Facts and Figures 2011. http://www.cancer.org/acs/groups/content/@epidemiologysurveilance/documents/document/acspc-029771.pdf
2 Global Solar UV Index. World Health Organization. http://www.who.int/uv/publications/en/UVIGuide.pdf
3 Neale, R, Williams, G, Green, A. Application patterns among participants randomized to daily sunscreen use in a skin cancer prevention trial. Arch Dermatol. 2002 Oct; 138, 1319-1325.
4 Report on Carcinogens, Eleventh Edition (Ultraviolet Radiation Related Exposures); U.S. Department of Health and Human Services, Public Health Service, National Toxicology Program.
5 Holloway L. Atmospheric sun protection factor on clear days: its observed dependence on solar zenith angle and its relevance to the shadow rule for sun protection. Photochem Photobiol 1992;56:229-34.
6 Hemminki K, Dong C. Subsequent cancers after in situ and invasive squamous cell carcinoma of the skin. Arch Dermatol 2000;136:647-51.