@inbook{3411571, author={Harvey J. Blumenthal and Alan M. Rapoport}, editor={Warfield, Carol A. and Bajwa, Zahid H.}, title={Chapter 20. Common 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=3411571} }