ATLASGAL-selected massive clumps in the inner Galaxy - IX. Deuteration of ammonia M. Wienen, F. Wyrowski, C. M. Walmsley, T. Csengeri, T. Pillai, A. Giannetti and K. M. Menten A&A, 649 (2021) A21 Published online: 03 May 2021 DOI: 10.1051/0004-6361/201731208