SIMBAD references

We present the results of two-band CCD photometric monitoring of the gravitationally lensed quasar Q0142-100 (UM 673). The data, obtained at ESO-La Silla with the 1.54m Danish telescope in the Gunni-band (October 1998-September 1999) and in the Johnson V-band (October 1998 to December 2001), were analyzed using three different photometric methods. The light-curves obtained with all methods show variations, with a peak-to-peak amplitude of 0.14mag in V. Although it was not possible to measure the time delay between the two lensed QSO images, the brighter component displays possible evidence for microlensing: it becomes bluer as it gets brighter, as expected under the assumption of differential magnification of a quasar accretion disk.