[R] Ubuntu jaunty - R can't be install

[Veyssière Marine]

Dear helpers,
I would like to install R on a computer with Ubuntu Jaunty. 
Unfortunately, Jaunty  does not  appear in any CRAN mirror website I  
have tried (France, Canada, Italy, Germany).
Could you give me any mirror website  allowing installation on 
Jaunty?or  could you give me a procedure to passby this problem?

Thanks for your help,
Best regards,
Marine Veyssière