@misc{indiciaec346c9fa6dcd,
  title = {Photographic subtraction. II. Technical aspects and method.},
  author = {C Hårdstedt and B Rundelius and U Welander},
  year = {1976},
  doi = {10.1177/028418517601700110},
  url = {https://pubmed.ncbi.nlm.nih.gov/773109/},
  note = {Source identifier: 773109}
}