@misc{indiciae92436f64cc8e,
  title = {Vitamin D, example and challenge.},
  author = {E Havinga},
  year = {1973},
  doi = {10.1007/bf01935064},
  url = {https://pubmed.ncbi.nlm.nih.gov/4758912/},
  note = {Source identifier: 4758912}
}