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Audubon's Birds of America fetches £7.3m at auction

7 December 2010 Last updated at 23:02 GMT

The world's most expensive book, a copy of John James Audubon's Birds of America, has sold at auction for just over £7.3m.

Only 119 complete copies of the 19th Century book are known to exist, with 108 owned by museums and libraries.

Will Gompertz reports.