UBVRI photometric sequences for symbiotic stars

Deep, wide-range and accurate UBVRI photometric sequences have been established around more than 80 symbiotic stars, to assist current photometry as well as measurement of old photographic plates. Sequences for 40 symbiotic stars have already been published; the observations for the others have already been secured.
To appear in the proceedings of "Symbiotic stars probing stellar evolution", R.L.M. Corradi, J. Mikolajewska and T.J. Mahoney eds., ASP Conference Series, 2002, in press