McGraw-Hill Concise Encyclopedia of Engineering. VideotelephonyArxivləşdirilib 2020-03-04 at the Wayback Machine, McGraw-Hill, 2002. Retrieved from the FreeDictionary.com website, January 9, 2010
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McGraw-Hill Concise Encyclopedia of Engineering. VideotelephonyArxivləşdirilib 2020-03-04 at the Wayback Machine, McGraw-Hill, 2002. Retrieved from the FreeDictionary.com website, January 9, 2010