Time trends of vitamin D concentrations in northern Sweden between 1986 and 2014: a population-based cross-sectional study.
Summerhays E, Eliasson M, Lundqvist R, Söderberg S, Zeller T, Oskarsson V.
Eur J Nutr. 2020 Oct;59(7):3037-3044. doi: 10.1007/s00394-020-02142-x. PMID: 31754783.