@misc{indiciaeca9673dda3ad,
  title = {[Fixed rule: variability].},
  author = {A Bracchetti and G Bracchetti and G De Risky and G Tinarelli},
  year = {1985},
  url = {https://pubmed.ncbi.nlm.nih.gov/3867386/},
  note = {Source identifier: 3867386}
}