On Fri, Oct 9, 2009 at 10:24 PM, Rahul Sundaram
If it is a document, then it is better to choose a more appropriate
license targeted towards content. The close equivalent for content is
the Creative Commons Attribute Share Alike license
You have plenty of options there
Nevertheless, if you must use GPL, the license itself has a section
how to apply it.
You cannot interpret GPL on documents easily, even if it involves
source files (for creating the document). The latest GFDL may be
suitable. As of now the CC licenses are better.
ASL, CLC, AMS, CMS