  We show that as many as ~50 quasars with at least mJy-level expected flux
density can be pre-selected as potential in-beam phase-reference targets for
ASTRO-G. Most of them have never been imaged with VLBI. These sources are
located around strong, compact calibrator sources that have correlated flux
density >100 mJy on the longest VLBA baselines at 8.4 GHz. All the targets lie
within 12' from the respective reference source. The basis of this selection is
an efficient method to identify potential weak VLBI target quasars simply using
optical and low-resolution radio catalogue data. The sample of these dominantly
weak sources offers a good opportunity for a statistical study of their radio
structure with unprecedented angular resolution at 8.4 GHz.
