1. Armstrong, D. (1978). A theory of universals, Vol. 2: Universals and scientific realism. Cambridge: Cambridge University Press.
2. Bernstein, S. (2014). Two problems for proportionality about omissions. Dialectica, 68(3), 429–441.
3. Bernstein, S. (2015). The Metaphysics of Omissions. Philosophy Compass, 10(3), 208–218.
4. Dowe, P. (2004). Causes are physically connected to their Effects: Why preventers and omissions are not causes. Hitchcock, C. Contemporary Debates in the philosophy of Science (pp. 189–196). Blackwell.
5. Dowe, P. (2010). Proportionality and Omissions. Analysis, 70(3), 446–451.