Age, vitamin D, and solar ultraviolet.

@article{Holick1989AgeVD,
  title={Age, vitamin D, and solar ultraviolet.},
  author={Michael F Holick and Lois Y Matsuoka and Jacobo Wortsman},
  journal={Lancet},
  year={1989},
  volume={2 8671},
  pages={1104-5}
}