Version 3.0 September 2009	Approximately 2000 new transitions have been added to the recommended rest frequency table, which now lists more than 12000 entries This report updates the previous summaries, provides a current source of radio-astronomical molecular line observations, and improves the accuracy for many previously tabulated transition frequencies, important for determining physical properties of the molecular clouds investigated. A few minor corrections were made for some of the references.
Journal Publication March 2004	NIST Recommended Rest Frequencies for Observed Interstellar Molecular Microwave Transitions - 2002 Revision J. Phys. Chem. Ref. Data 33(1), 177-355 (2004).
Version 2.0.1 February 2004	For formatted output, the formula "HC11N" was corrected to be "HC11N." Complete citation information was added for the March 2004 JPCRD journal publication.
Version 2.0 August 2003	Approximately 5600 new transitions and 31 new molecular species have been added to this tabulation, which now lists more than 10,100 entries. This report updates the previous summaries, provides a current source of radio-astronomical molecular line observations, and improves the accuracy for many previously tabulated transition frequencies, important for determining physical properties of the molecular clouds investigated. (Update based on the above March 2004 JPCRD journal publication.)
Version 1.1 August 2001	Minor revisions were made to the web interface.
Version 1.0 April 1996	Web version made available online. (Created by André Pool, November 1995.)
Journal Publication 1992	NIST Recommended Rest Frequencies for Observed Interstellar Molecular Microwave Transitions - 1991 Revision J. Phys. Chem. Ref. Data 21(2), 181-272 (1992).