Long-term R and V-band monitoring of some suitable targets for the link between ICRF and the future Gaia celestial reference frameF. Taris, A. Andrei, J. Roland, A. Klotz, F. Vachier and J. SouchayA&A, 587 (2016) A112DOI: https://doi.org/10.1051/0004-6361/201526676
