XML-based format for educational test / quizes

Hello mailing list,

I wonder if there is any existing XML-based format for educational tests 
(or quizes). I'm at the beginning of development of a unified testing 
software and need to make a decision how to store data. The only thing I 
  know at the moment is that for some reasons it must be XML-based 
format, not DB.

Thanks in advance.

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Michael Klishin,

E-mail / MSN :