The P Cygni supergiant [OMN2000] LS1 – implications for the star formation history of W51J. S. Clark, B. Davies, F. Najarro, J. MacKenty, P. A. Crowther, M. Messineo and M. A. ThompsonA&A, 504 2 (2009) 429-435DOI: https://doi.org/10.1051/0004-6361/200911980