  We present results of the spectroscopical follow-up observations of QSO
candidates from a combined variability and proper motion (VPM) survey in a ~10
square degrees region centered on the globular cluster M3. The search is based
on a large number of digitised Schmidt plates with a time-baseline of three
decades. This paper reviews the candidate selection, the follow-up
spectroscopy, and general properties of the resulting QSO sample. In total, 175
QSOs and Sey1s were identified among the objects from the VPM survey, with 114
QSOs and 10 Sey1s up to the pre-estimated 90% completeness limit of the survey
at B_lim~19.7. The redshift range of the QSOs is 0.4<z<3. Among the 80 QSO
candidates of highest priority we confirm 75 QSOs/Sey1s and 2 NELGs. We present
magnitudes, colours, redshifts, and variability indices for all 181 identified
QSOs/Sey1s/NELGs and spectra for the 77 QSOs/Sey1s/NELGs from our spectroscopic
follow-up observations. The VPM survey uses selection criteria that are not
directly relying on the spectral energy distribution of QSOs. It is therefore
remarkable that the properties of the VPM QSOs do not significantly differ from
those of samples from colour selection or slitless spectroscopy. In particular,
we do not detect a substantial number of unusually red QSOs. The total surface
density of the brighter QSOs (17<=B<=18.5) in our search field is found to be
by a factor of ~1.8 larger than that derived from previous optical surveys.
