total number of sources                           270
quasars (QSO)                                     132
  redshifts known                                 122
  missing redshifts                                10
galaxies (GAL)                                    104
  uncertain classification                          2
  redshifts known                                  90
  missing redshifts                                14
BL Lac objects (both types)                        12
  BL/GAL                                            4
  BL/QSO                                            8
  redshifts known                                   7
  uncertain redshifts                               1
  lower limit for redshifts                         1
  missing redshifts                                 3
empty fields (EF)                                  22
sources with flat radio spectra (s(11-6) >= -0.5) 144
  quasars                                          99
  galaxies                                         26
  BL Lac objects                                   11
  empty fields                                      8
sources with steep radio spectra (s(11-6) < -0.5) 126
  quasars                                          33
  galaxies                                         78
  BL Lac objects                                    1
  empty fields                                     14