1. Ground-based terahertz CO spectroscopy towards Orion
2. A Map of OMC‐1 in COJ= 9→8
3. The Cologne Database for Molecular Spectroscopy can be accessed free of charge at http://www.ph1.uni-koeln.de/vorhersagen/. An alias is also available: http://www.cdms.de/.
4. The Cologne Database for Molecular Spectroscopy, CDMS
5. Proceedings of the Fourth Cologne–Bonn–Zermatt-Symposium ‘The Dense Interstellar Medium in Galaxies’; September 22–26, 2003, Zermatt, Switzerland;Müller,2004