1. H. E. Swanson, N. T. Gilfrich andG. M. Ugrinig, “Standard X-ray diffraction patterns”, National Bureau of Standards Circular,539 (1955) 6.
2. J. M. Mery,Acta Cryst. 8 (1955) 840.
3. Wyckoff, “Crystal Structure” Vol. 1 (John Wiley, New York, 1966) p. 24.
4. M. U. Cohen,Rev. Sci. Instr. 6 (1935) 68.