Lanzendorf, E.J., T.F. Hanisco, P. Wennberg, R.C. Cohen, R.M. Stimpfle, J.G. Anderson, R. Gao, J. Margitan, and T.V. Bui (2001), Establishing the dependence of [HO2]/[OH] on temperature, halogen loading, O3, and Nox based on in situ measurements from the NASA ER-2, J. Phys. Chem. A, 105, 1535-1542.