Berry, C. (2011). The sustainable procurement guide: Procuring sustainably using BS 8903. BSi.
Chicago Style (17. basım) AtıfBerry, Cathy. The Sustainable Procurement Guide: Procuring Sustainably Using BS 8903. London: BSi, 2011.
MLA (8th ed.) AtıfBerry, Cathy. The Sustainable Procurement Guide: Procuring Sustainably Using BS 8903. BSi, 2011.
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