list sports managers who managed sheffield united f . c . and ethnikos piraeus f . c . ?
SELECT DISTINCT var_uri where brack_open var_uri dbo_managerClub dbr_Sheffield_United_F.C sep_dot sep_dot var_uri dbp_managerclubs dbr_Ethnikos_Piraeus_F.C sep_dot sep_dot var_uri a dbo_SportsManager brack_close