Organisation for Economic Co-operation and Development. (1991). United Kingdom: 1990/1991. OECD Publishing.
Chicago-referens (17:e uppl.)Organisation for Economic Co-operation and Development. United Kingdom: 1990/1991. Paris: OECD Publishing, 1991.
MLA-referens (9:e uppl.)Organisation for Economic Co-operation and Development. United Kingdom: 1990/1991. OECD Publishing, 1991.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.