Welford, R. (1988). The economics manuel skills at and AS level (3rd ed.). framework.
Chicago Style (17. basım) AtıfWelford, Richard. The Economics Manuel Skills at and AS Level. 3rd ed. Lancaster: framework, 1988.
MLA (9th ed.) AtıfWelford, Richard. The Economics Manuel Skills at and AS Level. 3rd ed. framework, 1988.
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