Cho, J.Y.N., R.E. Newell, T.P. Bui, E.V. Browell, M.A. Fenn, M.J. Mahoney, G.L. Gregory, G.W. Sachse, S.A. Vay, T.L. Kucsera, and A.M. Thompson (1999), Observations of convective and dynamical instabilities in tropopause folds and their contribution to stratosphere-troposphere exchange, J. Geophys. Res., 104, 21549-21568.