Restricted accessReview articleFirst published online 1992-02
Book Reviews : L. Sechrest,E. Perrin,and J. Bunker (Eds.). Research Methodology: Strengthening Causal Interpretations of Nonexperimental Data. (AHCPR Conference Proceedings,Tucson,AZ,April,1987). Washington,DC: U.S. Department of Health and Human Services,Public Health Service,Agency for Health Care Policy and Research,1990