MathML Presentation to content transformation

Good afternoon,
i am looking for transformation tools that convert MathML Presentation markup expressions to MathML Content markup expressions (i suppose that the transformation process is context-dependent). Do you know if  tools or works (documents, ...) in this direction have been done? Thank you for your help,
i look forward to hearing from you,
Best regards,

*********************************************************
Benoit Encelle
TOBIA Team, IRIT, University Paul SABATIER
118, route de Narbonne
31062 Toulouse cedex 4
Tel : +33 5 61 55 69 44
Fax : +33 5 61 55 82 03