SIMBAD references

A sample of BL Lac objects at radio wavelengths with arcsecond and milliarcsecond resolution is investigated. The sample consists of 30 objects, with redshift z<0.2 and all previously observed with HST. The objects, nearby and mostly X-ray selected, are weak in the radio and little information in this band is available. The observations with the VLA, VLBA, EVN and MERLIN are completed. We present and discuss the morphology of the objects and the overall properties of the sample. In particular, the parent population and a comparison to the optical HST nuclei are considered.