Surveying the inner structure of massive young stellar objects using L-band spectroscopy Andrew G. Barr, Jialu Li, Adwin Boogert, Amanda Lee, Curtis N. DeWitt and Alexander G. G. M. Tielens A&A, 666 (2022) A26 Published online: 30 September 2022 DOI: 10.1051/0004-6361/202143003