1. Chandran V, Raychaudhuri SP. Geoepidemiology and environmental factors of psoriasis and psoriatic arthritis. J Autoimmun. 2010;34(3):J314–21.
2. Shah SK, Arthur A, Yang YC, Steven S, Alexis AF. A retrospective study to investigate racial and ethnic variations in the treatment of psoriasis with etanercept. J Drugs Dermatol. 2011;10(8):866–72.
3. Bolognia JL, Jorizzo JL, Schaffer JV. Dermatology, vol. 1. 3rd ed. China: Elsevier; 2012. p. 135–55.
4. Gelfand JM, Stern RS, Nijsten T, Feldman SR, Thomas J, Kist J, Rolstad T, Margolis DJ. The prevalence of psoriasis in African Americans: results from a population-based study. J Am Acad Dermatol. 2005;52(1):23–6.
5. Kelly AP, Taylor SC, editors. Dermatology for skin of color. New York: McGraw Hill; 2009. p. 139–45.