Multifrequency observations of Blazars

This paper reports the results of a programme of multifrequency observations of a sample of Blazars concentrating particularly on the millimetre through infrared region. The authors' observations have demonstrated the need for a new model to explain the spectral behaviour of a major flare in 3C 273. This also provides a good description of the variability exhibited by Blazars. The authors have also shown that the radio through mid-IR synchrotron spectrum of 3C 273 is a separate component from the optical/IR