1. The clinical syndrome of chronic pain;Black,1980
2. Psychological predictors of success or failure of surgical intervention for intractable back pain;Blumetti,1976
3. The ‘learned pain syndrome’;Brena;Postgrad. Med.,1981
4. A ‘pain estimate’ model for quantification and classification of chronic pain states;Brena;Anesthesiol. Rev.,1975
5. Chronic back pain: electromyographic, motion and behavioral assessments following sympathetic nerve blocks and placebos;Brena;Pain,1980