@misc{indiciae31f0e75f572e,
  title = {Cluster headache.},
  author = {Frederick G Freitag},
  year = {2004},
  doi = {10.1016/j.pop.2004.02.005},
  url = {https://pubmed.ncbi.nlm.nih.gov/15172509/},
  note = {Source identifier: 15172509}
}