@misc{indiciaeaa7888a16d83,
  title = {Issues in studying ancillary services.},
  author = {L L Roos},
  year = {1982},
  doi = {10.1016/0277-9536(82)90169-1},
  url = {https://pubmed.ncbi.nlm.nih.gov/6813974/},
  note = {Source identifier: 6813974}
}