The spectral variability of HD 192639 and its implications for the star's wind structure G. Rauw, N. D. Morrison, J.-M. Vreux, E. Gosset and C. L. Mulliss A&A, 366 2 (2001) 585-597 Published online: 15 February 2001 DOI: 10.1051/0004-6361:20000106