@misc{indiciae5513ddbc6618,
  title = {Operant behavior in the morphine-dependent rhesus monkey.},
  author = {S G Holtzman and J E Villarreal},
  year = {1973},
  url = {https://pubmed.ncbi.nlm.nih.gov/4631467/},
  note = {Source identifier: 4631467}
}