RT Journal Article SR Electronic T1 Clinical Observations on the Mechanism of Hypertensive Headache and the Results of its Treatment with Dihydroergotamine Tartrate JF Cleveland Clinic Journal of Medicine JO Cleve Clin J Med FD Cleveland Clinic SP 227 OP 231 VO 13 IS 4 A1 Birchall, Robert A1 Taylor, Robert D. A1 Page, Irvine H. YR 1946 UL http://www.ccjm.org/content/13/4/227.abstract AB