DB : Who is using the temp tablespace

SELECT b.tablespace,
          ROUND(((b.blocks*p.value)/1024/1024),2)||'M' "SIZE",
          a.sid||','||a.serial# SID_SERIAL,
          a.username,
          a.program
     FROM sys.v_$session a,
          sys.v_$sort_usage b,
          sys.v_$parameter p
    WHERE p.name  = 'db_block_size'
      AND a.saddr = b.session_addr
   ORDER BY b.tablespace, b.blocks;