Scientific journal publication Estimated equivalency of vitamin D production from natural sun exposure versus oral vitamin D supplementation across seasons at 2 U.S. latitudes. Terushkin, V, Bender, A.; Psaty, E.L.; Engelsen, O.; Wang, S.Q.; Halpern, A.C. Publication details Journal: J. Am. Acad. Dermatol., 62, 929.e1–929.e9, 2010 DOI: 10.1016/j.jaad.2009.07.028