Keim, E.R., S.A. McKeen, R. Gao, S.G. Donnelly, R.C. Wamsley, L.A. DelNegro, D. Fahey, T.F. Hanisco, E.J. Lanzendorf, M. Proffitt, J. Margitan, E. Hintsa, L. Jaeglé, C.R. Webster, R. May, D.C. Scott, R. Salawitch, J. Wilson, C.T. McElroy, E. Atlas, F. Frocke, and T.P. Bui (1999), NOy partitioning from measurements of nitrogenand hydrogen radicals in the upper troposphere, Geophys. Res. Lett., 26, 51-54.