Empirical mass-loss rates and clumping properties of Galactic early-type O supergiantsC. Hawcroft, H. Sana, L. Mahy, J. O. Sundqvist, M. Abdul-Masih, J. C. Bouret, S. A. Brands, A. de Koter, F. A. Driessen and J. PulsA&A, 655 (2021) A67DOI: https://doi.org/10.1051/0004-6361/202140603