1. Armstrong, D. (1989). Universals: An opinionated introduction. Boulder, CO: Westview Press.
2. Armstrong, D. (1997). A world of states of affairs. Cambridge: Cambridge University Press.
3. Bergmann, G. (1967). Realism: A critique of brentano and meinong. Madison, WI: University of Wisconsin Press.
4. Bobik, J. (1961). St. Thomas on the individuation of bodily substances. In H. Koren (Ed.), Readings in the philosophy of nature (pp. 327–340). Westminster, MD: The Newman Press.
5. Bobik, J. (1965). Aquinas on being and essence: A translation and interpretation. Notre Dame, IN: University of Notre Dame Press.