@misc{indiciae28b738174b3e,
  title = {Preference in concurrent variable-interval fixed-ratio schedules.},
  author = {M Davison},
  year = {1982},
  doi = {10.1901/jeab.1982.37-81},
  url = {https://pubmed.ncbi.nlm.nih.gov/16812261/},
  note = {Source identifier: 16812261}
}