Distances and ages of NGC 6397, NGC 6752 and 47 TucR. G. Gratton, A. Bragaglia, E. Carretta, G. Clementini, S. Desidera, F. Grundahl and S. LucatelloA&A, 408 2 (2003) 529-543DOI: https://doi.org/10.1051/0004-6361:20031003
