Medication overuse headache in Canada.
Becker
W J
WJ
Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada.
Purdy
R A
RA
D001294:Attitude to Health; D002170:Canada / Q000453:epidemiology; D051271:Headache Disorders, Secondary / Q000453:epidemiology* / Q000628:therapy; D006801:Humans