@misc{indiciaea98e897cfd00,
  title = {An accurate system for evaluating gamma ray collimators.},
  author = {L W Oberley and S C Lensink and J C Ehrhardt and J H Christie},
  year = {1974},
  doi = {10.1088/0031-9155/19/1/003},
  url = {https://pubmed.ncbi.nlm.nih.gov/4438442/},
  note = {Source identifier: 4438442}
}