DocBook: The Definitive Guide - Copyright Problem

Hello,

  I'm mailing you because i just read the copyright on
http://www.docbook.org/tdg/en/html/dbcpyright.html . I never used
docbook before because I thought that the reference book was NOT free,
as i read it at
http://www.oreilly.com/catalog/docbook/chapter/book/rights.html.

The (c) on oreilly.com says, we are NOT allowed to redistribute the
document; whereas, the (c) on docbook.org says the book is under FDL, wich
would allow me to modify and redistribute it, without the previous
permission of oreilly.

Which is the correct one? Can I redistribute the oreilly reference book,
or not? I don't really anderstand why there are two licenses... is this a
mistake?


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