Consumers can look up any ISSN at WorldCat.org, according to the U.S. ISSN Center. The center assigns International Standard Serial Numbers to every serial printed in the United States. More »

Canadian phone numbers can be found online at websites like Canada 411 or Canada Cell Phone Number Directory. Information can be searched by name, number or location. More »

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To find a listing with an MLS number, visit Realtor.com. In the For Sale search box, click on Search by MLS ID, located under the price range boxes. Enter the MLS ID, and click Search. More »

Many self-publishing platforms, such as CreateSpace and Smashwords, offer free ISBN numbers to customers who publish through their imprint. A free ISBN number often comes with restrictions on the marketing and distributi... More »

A stock keeping unit, or SKU, is a distinct combination of letters and numbers assigned to a particular product sold by a business. The primary purpose a stock keeping unit is to allow effective inventory tracking and to... More »

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Universal Product Code (UPC) barcode numbers work by assigning a meaning to each of a series of twelve numbers, according to HowStuffWorks. UPC barcodes are derived from the Uniform Code Council, the company that operate... More »

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To find fax numbers for businesses, type the business name into an online phone directory such as White Pages or Yellow Pages. Scroll through the business information and select the number listed as "fax." More »