  The main criterium for the selection of active objects in the First Byurakan
Survey was the presence of uv-excess on low-dispersion spectra registered on
photographic plates obtained with the 1m Shmidt type Byurakan telescope. Using
the presence of emission lines as the second criterium became possible during
the Second Byurakan Survey due to its improved technique. Through this
criterium a majority of objects, extended by morphology, were selected into the
separate "sample of galaxies". Certainly, there were cases of untrue selection,
particularly, on faint magnitudes, when absorption lines were taken for
emission ones and so on. Study of SBS galaxies, including evaluation of an
effectivity of selection criteria, was undertaken by means of complex
investigation of their very representative part, pooled in our basic sample.
The completion of the follow-up slit spectroscopy of these about 500 objects
formed the main stage of implementation of this program. Also, the scheme was
developed to provide homogeneous classification, directed, in particular, to
separate galaxies of AGN activity, of known types, and starforming, SfG,
activity. For starforming galaxies, which constitute more than 80% of the basic
sample, we provided two classes, SfGcontinual and SfGnebular. Averaged
statistics of our SfG galaxies show, that every fifth of them is in more
active, nebular phase of starforming activity, most of which are known as blue
compact galaxies. However, it must be noted, that, by the analysis, namely for
the latter objects, the effectiveness of the survey is the highest, so that
BCGs represent the best product of SBS among extended objects. Aimed on further
specifications in classification of SfG galaxies, other generalizations and
statistics in frames of ongoing investigation, detailed studies of individual
galaxies are currently beeing held, based on data of panoramic spectroscopy.
