8Cheung, S., 1970, "The Structure of a Contract and the Theory of a Non-exclusive Resource", Journal of Law and Economics, 13, 49-70.
9Coase, R., 1960, "The Problem of Social Cost", Journal of Law and Economics, 3, 1-44.
10European Commission, 2008, "Questions and Answers on the Commission's Proposal to Revise the EU Emissions Trading System", MEMO/ 08/35, Brussels, 23 January.