The optical gravitational lensing experiment. Variable stars in globular clusters. I. Fields 5139A-C in ω CentauriJ. Kaluzny, M. Kubiak, M. Szymański, A. Udalski, W. Krzemiński and M. MateoAstron. Astrophys. Suppl. Ser., 120 1 (1996) 139-152DOI: https://doi.org/10.1051/aas:1996280