@misc{indiciaed3d82105be58,
  title = {Drug discrimination under concurrent variable-ratio variable-ratio schedules.},
  author = {D E McMillan and W C Hardwick and Mi Li},
  year = {2002},
  doi = {10.1901/jeab.2002.77-91},
  url = {https://pubmed.ncbi.nlm.nih.gov/11831785/},
  note = {Source identifier: 11831785}
}