Establishing the evolutionary timescales of the massive star formation process through chemistryG. Sabatini, S. Bovino, A. Giannetti, T. Grassi, J. Brand, E. Schisano, F. Wyrowski, S. Leurini and K. M. MentenA&A, 652 (2021) A71DOI: https://doi.org/10.1051/0004-6361/202140469