@misc{indiciaef14cd9cd1982,
  title = {Sferics and headache: a prospective study.},
  author = {H Walach and H D Betz and A Schweickhardt},
  year = {2001},
  doi = {10.1046/j.1468-2982.2001.00230.x},
  url = {https://pubmed.ncbi.nlm.nih.gov/11531901/},
  note = {Source identifier: 11531901}
}