O’Sullivan, F, Laird, E, Kelly, D, van Geffen, J, van Weele, M, McNulty, H, Hoey, L, Healy, M, McCarroll, K, Cunningham, C, Casey, M, Ward, M, Strain, JJ, Molloy, AM & Zgaga, L. 2017 Ambient UVB Dose and Sun Enjoyment Are Important Predictors of Vitamin D Status in an Older Population. The Journal of nutrition, vol. 147, no. 5, pp. 858-868. https://doi.org/10.3945/jn.116.244079