1. Armstrong, David Malet, 1997, A World of States of Affairs, Cambridge University Press, Cambridge.
2. Armstrong, David Malet, 1989, Universals. An Opinionated Introduction, Westview, Boulder.
3. Armstrong, David Malet, 1978, Universals and Scientific Realism, vol. 1: Nominalism and Realism, vol. 2: A Theory of Universals, Cambridge University Press, Cambridge.
4. Bealer, George, 1994, “Property Theory: The Type-Free Approach v. the Church Approach”, Journal of Philosophical Logic, vol. 23, pp. 139-171.
5. Bealer, George, 1989, “Fine-Grained Type-Free Intensionality”, en Gennaro Chierchia, Barbara H. Partee y Raymond Turner 1989, pp. 177-230.