  We describe the source subtraction strategy and observations for the extended
Very Small Array, a CMB interferometer operating at 33 GHz. A total of 453
sources were monitored at 33 GHz using a dedicated source subtraction baseline.
131 sources brighter than 20 mJy were directly subtracted from the VSA
visibility data. Some characteristics of the subtracted sources, such as
spectra and variability, are discussed. The 33-GHz source counts are estimated
from a sample selected at 15 GHz. The selection of VSA fields in order to avoid
bright sources introduces a bias into the observed counts. This bias is
corrected and the resulting source count is estimated to be complete in the
flux-density range 20-114 mJy. The 33-GHz source counts are used to calculate a
correction to the VSA power spectrum for sources below the subtraction limit.
