1. and Misused Statistics, Marcel Dekker, New York, 1987, p. 1.
2. and (eds.) Comorbidity of Mood and Anxiety Disorders, American Psychiatric Press, Washington, 1990.
3. Clinical Judgment, Robert E. Krieger Publishing Company, New York, 1967 (especially pp. 153–154).
4. Clinimetrics, Yale University Press, New Haven, 1987.
5. The pre-therapeutic classification of co-morbidity in chronic disease