Metallicity and the spectral energy distribution and spectral types of dwarf O-stars M. R. Mokiem, N. L. Martín-Hernández, A. Lenorzer, A. de Koter and A. G. G. M. Tielens A&A, 419 1 (2004) 319-334 Published online: 23 April 2004 DOI: 10.1051/0004-6361:20040074