@misc{indiciae45261a67f7f7,
  title = {Incentive effects and competing response models.},
  author = {D Birch and F P Valle},
  year = {1967},
  doi = {10.2466/pr0.1967.20.1.263},
  url = {https://pubmed.ncbi.nlm.nih.gov/6037804/},
  note = {Source identifier: 6037804}
}