@misc{indiciaec9be2fdc54bb,
  title = {Preference for signalled reinforcement.},
  author = {P Lewis and L Lewin and P Muehleisen and M Stoyak},
  year = {1974},
  doi = {10.1901/jeab.1974.22-143},
  url = {https://pubmed.ncbi.nlm.nih.gov/16811773/},
  note = {Source identifier: 16811773}
}