@inbook{3411161,
author={Gerald W. Smetana},
editor={Warfield, Carol A. and Bajwa, Zahid H.},
title={Chapter 18. Historical Features in Primary Headache Syndromes},
booktitle={Principles & Practice of Pain Medicine, 2e},
publisher={The McGraw-Hill Companies},
address={New York, NY},
year={2004},
url={accessanesthesiology.mhmedical.com/content.aspx?aid=3411161}
}