van Dishoeck, E. F. Infrared and Submillimeter Astronomy, MPI for Extraterrestrial Physics, Max Planck Society;
Van der Tak, F. F. S., Marseille, M. G., Herpin, F., Wyrowski, F., Baudry, A., Bontemps, S., et al. (2010). Water abundance variations around high-mass protostars: HIFI observations of the DR21 region. Astronomy & Astrophysics, 518: L107, pp. 1-5. doi:10.1051/0004-6361/201014515.