SACHS, W. S. (1981). Product Planning And Management/william S.sachs. PennWell Books.
Lua i Stíl Chicago (17ú heag.)SACHS, William S. Product Planning And Management/william S.sachs. PennWell Books, 1981.
Lua MLA (8ú heag.)SACHS, William S. Product Planning And Management/william S.sachs. PennWell Books, 1981.
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