1. Manchee, E. B., and Weichert, D. H., Bull. Seism. Soc. Amer., 58, 1359 (1968).
2. Vinnik, L. P., and Nikolayev, A. V., Izv. Akad. Nank. Fiz. Zemlya., 11, 24 (1970).
3. Capon, J., Semiannual Technical Summary, Seismic Discrimination (M.I.T., Lincoln Laboratory, 1972).
4. Greenfield, R. J., and Sheppard, R. M., Bull. Seism. Soc. Amer., 59, 409 (1969).
5. Engdahl, E. R., and Felix, C. P., J. Geophys. Res., 76, 2706 (1971).