1. Reduced Cells
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3. On the symmetry of deformable crystals
4. Fischer, W. & Koch, E. (1983). International Tables for Crystallography, Vol. A, Space-Group Symmetry, edited by Th. Hahn. Dordrecht: Kluwer Academic Publishers.
5. Friedel, G. (1926). Leçons de Cristallographie, ch. 15, Nancy, Paris, Strasbourg: Berger-Levrault. [Reprinted (1964), Paris: Blanchard].