@misc{indiciaeb9fcd38d229b,
  title = {A token economy program evaluation with untreated control ward comparisons.},
  author = {R F Gripp and P A Magaro},
  year = {1971},
  doi = {10.1016/0005-7967(71)90071-4},
  url = {https://pubmed.ncbi.nlm.nih.gov/5556839/},
  note = {Source identifier: 5556839}
}