Organisation for Economic Co-operation and Development & ProQuest (Firm). (2007). OECD environmental performance reviews: Belgium. OECD.
Chicago-referens (17:e uppl.)Organisation for Economic Co-operation and Development och ProQuest (Firm). OECD Environmental Performance Reviews: Belgium. Paris: OECD, 2007.
MLA-referens (9:e uppl.)Organisation for Economic Co-operation and Development och ProQuest (Firm). OECD Environmental Performance Reviews: Belgium. OECD, 2007.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.