which city located on 2008 african volleyball championship u21 is also the stadium 2011–12 olympiacos f . c . season ?
SELECT DISTINCT var_uri where brack_open dbr_2011–12_Olympiacos_F.C._season dbp_stadium var_uri sep_dot dbr_2008_African_Volleyball_Championship_U21 dbp_cities var_uri brack_close