@misc{indiciae21ca78eeda57,
  title = {A comparison of response patterns on fixed-, variable-, and random-ratio schedules.},
  author = {E K Crossman and E J Bonem and B J Phelps},
  year = {1987},
  doi = {10.1901/jeab.1987.48-395},
  url = {https://pubmed.ncbi.nlm.nih.gov/16812500/},
  note = {Source identifier: 16812500}
}