Heyd, D. (1982). Supererogation: Its status in ethical theory. Cambridge Univ. Press.
Chicago Style (17th ed.) CitationHeyd, David. Supererogation: Its Status in Ethical Theory. Cambridge [u.a.]: Cambridge Univ. Press, 1982.
MLA (9th ed.) CitationHeyd, David. Supererogation: Its Status in Ethical Theory. Cambridge Univ. Press, 1982.
Warning: These citations may not always be 100% accurate.