Y. I. Izotov (1), G. Stasinska (2), G. Meynet (3), N. G. Guseva (1), T. X. Thuan (4) ((1) Main Astronomical Observatory, Kyiv, Ukraine, (2) LUTH, Observatoire de Meudon, France, (3) Geneva Observatory, Switzerland, (4) University of Virginia, Charlottesville, USA)
