1. Bakwin PS (1999) The encyclopedia of geochemistry. Kluwer Academic Publishers, Lancaster, p 65
2. Mitchell JFB, Johns TC, Ingram WJ, Lowe JA (2000) Geophys Res Lett 27:2977
3. Picard A, Davis RS, Gläser M, Fujii K (2008) Metrologia 45:149
4. APAT Agenzia per la protezione dell’ambiente e per i servizi tecnici—Annuario dei dati ambientali (2007)
5. European standard FDIS prEN 14211 (2004) Ambient air quality—standard method for the measurement of the concentration of nitrogen dioxide and nitrogen monoxide by chemiluminescence