The I wonder why... series reused ISBNs for different books.  

In the library where I cataloged them :
ISBN 0871974525 had eight distinct titles (9 in WorldCat)
ISBN 0871974533 had six (8 in WorldCat)

Geoffrey Hooker 
http://geoffreyhookermls.blogspot.com/
It is dangerous to be right when the government is wrong. -Voltaire (1694-1778) 

On 20 May 2013 13:02, Shlomo Sanders <[log in to unmask]> wrote:
Sorry, no numbers, but I have heard complaints of different works having the same ISBN.

Thanks,
Shlomo

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