ISBN used more than once?

[Serkan]

http://www.goodreads.com/book/show/10...
This book is listed in worldcat and various bookseller sites by ISBN number 9753910347

http://www.goodreads.com/book/show/10...
However this book also uses the same ISBN and listed in worldcat with that isbn.

Is this an error of worldcat? Or did they use the ISBN in more than one book? How can i find out?

[Paula]

Use of the same ISBN is a reasonably common occurrence.

Information on how to handle here:

http://www.goodreads.com/help/show/26...