Diagnosing the Severe Headache
Neurol 44:S6-S12, Dalessio,D.J., 1994
Severe Headaches, When to Worry, What To Do
Postgrad Med 83:164-180, Drexler,E.D., 1990
Hemifacial Spasm, In Movement Disorders, A Comprehensive Survey
Futura Publ., NY. Ch. 9 p.510, Weiner,W.J. &LangA.E., 1989