@misc{indiciaef10053808102,
  title = {Relational learning in the pigeon.},
  author = {G Marsh},
  year = {1967},
  doi = {10.1037/h0025210},
  url = {https://pubmed.ncbi.nlm.nih.gov/6082893/},
  note = {Source identifier: 6082893}
}