Stringent upper limits to the solid NH3 abundance towards W 33A from near-IR spectroscopy with the Very Large TelescopeI. M. Taban, W. A. Schutte, K. M. Pontoppidan and E. F. van DishoeckA&A, 399 1 (2003) 169-175DOI: https://doi.org/10.1051/0004-6361:20021798
