1. A.R. Lang (1970) in Modern Diffraction and Imaging Techniques in Materials Science (ed S. Amelinckx R. Gevers, G.Remaut, J. van Landuyt,North Holland Amsterdam)p. 407
2. A. Authier (1978) in X-ray Optics (ed. H.-J. Queisser)Springer-Verlag p. 145
3. B.K. Tanner (1976) X-ray Diffraction Topography,Pergamon Press, Oxford
4. R.E. Green Jnr. (1971) Advances in X-ray Analysis 14, 311
5. W. Hartmann: in Ref. 2 p. 191