This invention is concerned with compounds of the formula
wherein one of R
5
, R
6
and R
7
is
and R
1
to R
13
, X
1
, X
2
, m and n are defined in the description, and all pharmaceutically acceptable salts and/or esters thereof. The invention further relates to pharmaceutical compositions containing such compounds, to a process for their preparation and to their use for the treatment and/or prevention of diseases which are modulated by PPARδ and/or PPARα agonists.