1. Ahmed, A. (2017). Exploiting cyclic preference. Mind, 126(504), 975–1022.
2. Åqvist, L. (1987). Introduction to deontic logic and the theory of normative systems. Naples: Bibliopolis.
3. Archer, A. (2018). Supererogation. Philosophy Compass, 13, 1–9.
4. Benn, C. (2017a). Supererogation, optionality, and cost. Philosophical Studies, 175(10), 2399–2417.
5. Benn, C. (2017b). Supererogatory spandrels. Ethics & Politics, 19(1), 269–290.