@misc{indiciae84419573785d,
  title = {Preference for conditioned reinforcement.},
  author = {B A Williams and R Dunn},
  year = {1991},
  doi = {10.1901/jeab.1991.55-37},
  url = {https://pubmed.ncbi.nlm.nih.gov/2002301/},
  note = {Source identifier: 2002301}
}