1. Cobreros, P. (2011). Supervaluationism and Fara’s argument concerning higher-order vagueness. In Égré, P. and Klinedinst, N. (eds), Vagueness and Language Use. Palgrave Macmillan.
2. Fara, D. G. (2003). Gap principles, penumbral consequence and infinitely higher-order vagueness. In Beall, J. C. (ed.), Liars and Heaps: New Essays on Paradox, pp. 195–221. Oxford University Press. Published under the name “Delia Graff.”
3. Fine, K. (1975). Vagueness, truth and logic. Synthese, 30: 265–300.
4. Keefe, R. (2000). Theories of Vagueness. Cambridge University Press, Cambridge, England.
5. Williamson, T. (1994) Vagueness. Routledge, London.