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The International Standard Book Number system was created in 1966 and standardized in 1970. Most of Stewart's books were published before the system was in place, and thus do not have ISBNs. His last books, published after 1970 (and those reprinted after that date), do have ISBNs, and they will be added to the article. Dwalls (talk) 05:42, 15 June 2009 (UTC)
Thank you. From what I already knew about ISBNs, I assumed that they could be applied retroactively. I guess not. Mapsax (talk) 22:16, 15 June 2009 (UTC)