1. See also Joseph Raz, The Argument from Justice, or How Not to Reply to Legal Positivism;Andrei Marmor;12 CANADIAN JOURNAL OF LAW AND JURISPRUDENCE,1999
2. The Many Faces of Legal Positivism
3. THE OXFORD HANDBOOK OF JURISPRUDENCE AND PHILOSOPHY OF LAW 104-116;See Andrei Marmor;ROUTLEDGE ENCYCLOPEDIA OF PHILOSOPHY,1996