1. Lipson, H., and Cochran, W., The Determination of Crystal Structures (Bell, London, 1953).
2. Goodman, P., and Lehmpfuhl, G., Acta Cryst., A,24, 339 (1968).
3. Hirsch, P. B., Howie, A., Nicholson, R. B., Pashley, D. W., and Whelan, M. J., Electron Microscopy of Thin Crystals (Butter-worths, London, 1965).
4. Pogany, A., and Turner, P. S., Acta Cryst., A,24, 107 (1968).
5. Howie, A., Proc. Fifth Eur. Cong. Electron Microscopy, 408 (Institute of Physics, London and Bristol, 1972).