1. Mellanby E (1920) Discussion on the importance of accessory food factors (vitamines) in the feeding of infants. Proc R Soc Med. 13(Sect Study Dis Child):95–98
2. Fraser WD, Tang JCY, Dutton JJ, Schoenmakers I (2019) Vitamin D measurement, the debates continue, new analytes have emerged, developments have variable outcomes. Calcif Tissue Int. https://doi.org/10.1007/s00223-019-00620-2
3. Cashman KD (2019) Vitamin D deficiency: defining, prevalence, causes and strategies of addressing. Calcif Tissue Int. https://doi.org/10.1007/s00223-019-00559-4
4. Institute of Medicine (US) (2011) Committee to Review Dietary Reference Intakes for Vitamin D and Calcium. In: Ross AC, Taylor CL, Yaktine AL, Del Valle HB (eds) Dietary Reference Intakes for Calcium and Vitamin D. National Academies Press, Washington (DC). http://www.ncbi.nlm.nih.gov/books/NBK56070/. Accessed 4 Dec 2019
5. The Scientific Advisory Committee on Nutrition (SACN) Vitamin D and health report. In: GOV.UK. https://www.gov.uk/government/publications/sacn-vitamin-d-and-health-report. Accessed 9 July 2019