Hall, B. D., G. S. Dutton and J. W. Elkins (2007), The NOAA nitrous oxide standard scale for atmospheric observations, Journal of Geophysical Research-Atmospheres, 112, 10.1029/2006JD007954.
Zhao, C. L. and P. P. Tans (2006), Estimating uncertainty of the WMO mole fraction scale for carbon dioxide in air, Journal of Geophysical Research-Atmospheres, 111(D8), 10.1029/2005JD006003.
Dlugokencky, E. J., R. C. Myers, P. M. Lang, K. A. Masarie, A. M. Crotwell, K. W. Thoning, B. D. Hall, J. W. Elkins and L. P. Steele (2005), Conversion of NOAA atmospheric dry air CH4 mole fractions to a gravimetrically prepared standard scale, JGR-Atmospheres, 110(D18), 10.1029/2005JD006035.
Zhao, C., P.P. Tans and K.W. Thoning (1997), A high precision manometric system for absolute calibrations of CO2 in dry air. Journal of Geophysical Research102(D5):5885-5894
Novelli, P. C., J. E. Collins, Jr., R. C. Myers, G. W. Sachse, and H. E. Scheel (1994), Reevaluation of the NOAA/ESRL carbon monoxide reference scale and comparisons with CO reference gasses at NASA-Langley and the Fraunhofer Institut, J. Geophys. Res., 99, No. D6, 12, 833-12, 839.
Novelli, P. C., J. W. Elkins and L. P. Steele (1991), The Development and Evaluation of a Gravimetric Reference Scale For Measurements of Atmospheric Carbon Monoxide, Journal of Geophysical Research-Atmospheres, 96(D7), 13109-13121, JD01108.