The ionising cluster of 30 Doradus - II. Spectral classification for 175 starsG. Bosch, R. Terlevich, J. Melnick and F. SelmanAstron. Astrophys. Suppl. Ser., 137 1 (1999) 21-41DOI: https://doi.org/10.1051/aas:1999480