1. Headache Classification Committee. The International Classification of Headache Disorders, 2nd Edition. Cephalalgia 2004; 24.
2. Daily chronic headache;Saper;Neurol Clin,1990
3. Chronic headache syndromes;Saper;Neurol Clin,1989
4. Drug induced headache;Mathew;Neurol Clin,1990
5. Ergotism: the clinical picture;Andersson,1988