1. Dobson, J. C., Kushida, E., Williamson, M. L. and Friedman, E. G. Intellectual performance of 36 phenylketonuric patients and their non-affected siblings.Pediatrics 58 (1976) 53–58
2. Koch, R., Azen, C. G., Friedman, E. G. and Williamson, M. L. Preliminary report on the effects of diet discontinuation in PKU.J. Pediatrics 100 (1982) 870–875
3. Williamson, M., Dobson, J. C. and Koch, R. Collaborative study of children treated for phenylketonuria: study design.Pediatrics 60 (1977) 815–821
4. Williamson, M. L., Koch, R., Azen, C. and Chang, C. Correlates of intelligence test results in treated phenylketonuric children.Pediatrics 68 (1981) 161–167