4) D. W. J. Cruickshank, “Computing Methods and the Phase Problem in X-ray Crystal Analysis,” ed by R. Pepinsky, J. M. Robertson, and J. C. Speakman, Pergamon Press, Oxford (1961), p. 45.
5) “International Tables for X-Ray Crystallography,” Kynoch Press, Birmingham (1968), Vol. III, pp. 201–206.