SIMBAD references

In the framework of an extensive program focusing on the global properties and evolution of active stars, high-precision UBV(RI)_c photometry of 19 selected stars, collected at the European Southern Observatory over the 15-31 March 1991 interval is presented. Significant evolution of the light curves, period variations and evidence for long-term variability of the global degree of spottedness are found. Most of the spectral classifications are discussed. A flare event was detected for the star HD 127535 = V 841 Cen. These observations contribute to the establishment of a time-extended photometric database which can give important clues on topics such as the stability of spotted areas, differential rotation, solar-like cycles and the correlation between inhomogeneities at different atmospheric levels.