It must be included in any conversation about famous sports quotes, and now the man who uttered the famous phrase is fighting to protect it.

Muhammad Ali, three-time World Heavyweight Champion, filed a lawsuit to stop a digital bookseller from using his iconic "Float like a butterfly, sting like a bee" saying in advertising without his approval.

Bloomberg reports a trademark infringement complaint was filed in Manhattan Federal Court yesterday, claiming Kobo, a company based in Toronto, used Ali's quote in a New York Times ad for its eReader.

Ali, 69, holds a registered trademark of the slogan, which he sells to third parties.

Ali last fought in 1981, losing to Trevor Berbick. He ended his pro boxing career with a 56-5 record, including 37 wins by knockout.

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