1. Adkins, A. W. H.: 1960, Merit and Responsibility. Clarendon Press, Oxford.
2. Baier, Kurt: 1958, The Moral Point of View. Cornell University Press, Ithaca, NY.
3. Benn, S. I. and R. S. Peters: 1959, Social Principles and the Democratic State. George Allen &; Unwin, London.
4. Bradley, F. H.: 1927, Ethical Studies. (2nd edn), Oxford University Press, London.
5. Carritt, E. F.: 1928, The Theory of Morals. Oxford University Press, London.