This excerpt taken from the PBR 6-K filed Jun 8, 2007.
Main accounting guidelines
The quarterly information has been produced in accordance with the accounting practices adopted in Brazil, the provisions deriving from Brazilian corporation law and the standards and procedures laid by the Brazilian Securities Commission - CVM.
No changes were made to the main accounting guidelines followed by the Company in relation to those stated in the 2006 annual report.
Certain balances relating to prior periods were reclassified in order to properly compare the interim financial information between the periods.