@misc{indiciae18416f3b6d69,
  title = {Understanding controlled trials. Crossover trials.},
  author = {B Sibbald and C Roberts},
  year = {1998},
  doi = {10.1136/bmj.316.7146.1719},
  url = {https://pubmed.ncbi.nlm.nih.gov/9614025/},
  note = {Source identifier: 9614025}
}