Não informado. (1971). Official Gazette of the United States Patent and Trademark Office. U.S. Department of Commerce.
শিকাগো স্টাইল (17 তম সংস্করণ) উদ্ধৃতিNão informado. Official Gazette of the United States Patent and Trademark Office. Washington: U.S. Department of Commerce, 1971.
M.L.A (8 ম সংস্করণ) উদ্ধৃতিNão informado. Official Gazette of the United States Patent and Trademark Office. U.S. Department of Commerce, 1971.
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