PAC, 1995, 67, 1913
(Nomenclature, symbols, units, and their usage in spectrochemical analysis-XV. Laser-based molecular spectroscopy for chemical analysis - laser fundamentals (IUPAC Recommendations 1995))
on page 1921
Transformed and rewritten from PDF version (entry
http://www.iupac.org/goldbook/O04325.pdf)
by: Miloslav Nic, Jiri Jirat, Bedrich Kosata, ICT Prague, Czech Republic