1. AAIDD 2017 Definition of intellectual disability. American Association on Intellectual and Developmental Disabilities http://aaidd.org/intellectual-disability/definition#.WsjYSy7wYdU
2. Amnesty International 2016 Death sentences and executions 2016 https://www.amnesty.org/download/Documents/ACT5057402017ENGLISH.PDF
3. Racial discrimination and the death penalty in the post-Furman era: An empirical and legal overview, with recent findings from Philadelphia;Baldus;Cornel Law Review,1998
4. Arbitrariness and discrimination in the administration of the death penalty: A legal and empirical analysis of the Nebraska experience (1973-1999);Baldus;Nebraska Law Review,2002