Singh, H., Y. Chen, G. L. Gregory, G. Sachse, R. Talbot, D. R. Blake, Y. Kondo, J. D. Bradshaw, B. Heikes, and D. Thornton (1997), Trace chemical measurements from the northern midlatitude lowermost stratosphere: distributions, correlations, and fate, Geophys. Res. Lett., 24, 127-130.