1. Mahl, H. Von, and Weitsch, W., Z. Naturf., 15 A, 1051 (1961).
2. Bassett, G. A., and Keller, A., Phil. Mag., 9, 817 (1964).
3. Ferrier, R. P., Proc. Third Eur. Reg. Conf. E.M., Prague, A, 115 (Czechoslovak Acad. Sci., 1964).
4. Terrier, R. P., unpublished work reported at Third Eur. Reg. Conf. E.M. Prague (1964).
5. Brenner, S., and Horne, R. W., Biochim. Biophys. Acta, 34, 103 (1959).