Evolution of massive protostars: the IRAS 18151–1208 region M. Marseille, S. Bontemps, F. Herpin, F. F. S. van der Tak and C. R. Purcell A&A, 488 2 (2008) 579-595 Published online: 17 July 2008 DOI: 10.1051/0004-6361:200809798