Wells, L. (1972). The product life cyle and nternational trade. Havard: President and Fellows of Havard College.
शिकागो स्टाइल उद्धरणWells, Louis. The Product Life Cyle and Nternational Trade. Havard: President and Fellows of Havard College, 1972.
एमएलए उद्धरणWells, Louis. The Product Life Cyle and Nternational Trade. Havard: President and Fellows of Havard College, 1972.
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