Currie, L. A., Benner, B. A., Cachier, H., Cary, R., Chow, J. C., Druffel, E. R., Eglinton, T. I., Gustafsson, O., Hartmann, P. C., Hedges, J. I., Kessler, J. D., Kirchstetter, T. W., Klinedinst, D. B., Klouda, G. A., Marolf, J. V., et al. (2002). A critical evaluation of interlaboratory data on total, elemental, and isotopic carbon in the carbonaceous particle reference material, NIST SRM 1649a, NIST J. Res., 107, 279-298