1. Elley, W. B. and Irving, J. C. Revised socioeconomic index for New ZealandNZ J. Educ. Stud. 11 (1976) 25
2. Guthrie, R. and Susi, A. A simple phenylalanine method for detecting phenylketonuria in large populations of newborn infants.Pediatrics 32 (1963) 338–343
3. Hiskey, M. S. Hiskey-Nebraska test of learning aptitude (revised), Manual. Union College Press, 1966
4. Koppitz, E. M.The Bender Gestalt test for young children. Grune and Stratton, New York, 1964.
5. Mamunes, P., Prince, P. E., Thornton, N. H., Hunt, P. A. and Hitchcock, E. S. Intellectural deficits after transient tyrosinemia in the term neonate.Pediatrics 57 (1976) 675–680