1. Armstrong DM (1989) Universals: An Opinionated Introduction. Westview Press, Boulder
2. Armstrong DM (1978) Nominalism and Realism. Cambridge University Press, Cambridge
3. Bergmann G (1947) Russell on Particulars. The Philosophical Review 56: 59–72 (reprinted in Klemke ED (ed) Essays on Bertrand Russell. University of Illinois Press, Urbana, 1970: 15–27)
4. Bergmann G (1967) Realism: A Critique of Brentano and Meinong. University of Wisconsin Press, Madison
5. Borghini A (2008) Why I Am Not A Tropist. In: Okada M, Smith B (eds) Proceedings of the First Interdisciplinary Ontology Meeting (InterOntology 2008). Keio University Press, Tokyo: 93–98