1. Greshko M et al. 2018. The sun, explained. National Geographic, 15 September, accessed August 2019. https://www.nationalgeographic.com/science/space/solar-system/the-sun/
2. ‘Our Sun In Depth’, NASA Science Solar System Exploration, 25 April 2019, accessed August 2019. https://solarsystem.nasa.gov/solar-system/sun/in-depth/
3. ‘Global Solar UV Index: A Practical Guide’, A Joint Recommendation of the World Health Organization, World Meteorological Organization, United Nations Environment Programme, International Commission on Non-Ionizing Radiation Protection, 2002, accessed September 2019, https://www.who.int/uv/publications/en/UVIGuide.pdf
4. Ferguson J, Dover JS. Photodermatology. 4th ed. London: Manson; 2010.
5. Young AR. The molecular and genetic effects of ultraviolet radiation exposure on skin cells. In: Hawk JLM, editor. Photodermatology. London: Chapman & Hall; 1998. p. 25–42.