WESTING J H. (1969). PURCHASING MANAGEMENT MATERIALS IN MOTION. JOHN WILEY AND SONS.
Lua i Stíl Chicago (17ú heag.)WESTING J H. PURCHASING MANAGEMENT MATERIALS IN MOTION. NEW YORK: JOHN WILEY AND SONS, 1969.
Lua MLA (9ú heag.)WESTING J H. PURCHASING MANAGEMENT MATERIALS IN MOTION. JOHN WILEY AND SONS, 1969.
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