1. 2) OECD : OECD Environmental Data Compendium 2008 (2008)
2. 4) The Council of the European Union : Article 10, In Council Directive 1999/31/EC of 26 April 1999 on the Landfill of Waste (1999)
3. 5) United States Government : Part 258-Criteria for Municipal Solid Waste Landfills, § 258.61 Post-closure Care Requirements (a), In Code of Federal Registration (1992)