1. Choca, J. P., Laastch, L., Wetzel, L., & Agresti, A. (1993). The Halstead category test: A fifty year perspective. In Paper presented at the annual meeting of the American Psychological Association, Toronto.
2. Costa, J., Santos, I., Silva, C., & DeFilippis, N. (2014). Portuguese norms of the Halstead category test: Preliminary data. In Presented at the 2014 national academy of neuropsychology conference, Puerto Rico.
3. DeFilippis, N. A., & McCampbell, E. (2002). Booklet category test. Paris: ECPA. French version of test with new norms and scales.
4. DeFilippis, N., & Reece, T. (2015). A statistical comparison of French vs US norms for the Booklet category test. In Presented at the national academy of neuropsychology annual convention, Austin, Nov 2015.
5. Halstead, W. C. (1940). Preliminary analysis of grouping behavior in patients with cerebral injury by the method of equivalent and non-equivalent stimuli. American Journal of Psychiatry, 96, 1263–1294.