Two-, three, and four-year follow-up on the self-regulatory treatment of chronic headache.
D000328:Adult; D000368:Aged; D001676:Biofeedback, Psychology; D002908:Chronic Disease; D005260:Female; D005500:Follow-Up Studies; D006261:Headache / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012064:Relaxation Therapy