Beevers Lipson method

Beevers, C. A., and Lipson, H. The crystal structure of copper sulphate pen-tahydrate, CuS04-5H20. Proc. Roy. Soc. (London) A146, 570-582 (1934). Lonsdale, K. An X-ray analysis of the structure of hexachlorobenzene using the Fourier method. Proc. Roy. Soc. (London) A133, 536-552 (1931). 

Bragg following advice to do so from his father, W. H. Bragg/ The calculations involved were many and tedious, and therefore Henry Lipson, C. Arnold Beevers, A. Lindo Patterson, and George Tunell provided more convenient methods of computing the electron-density functions in the days before high-speed computers were available. Currently, the computation of an electron-density map is simple and fast because of the efficiency of available computers. 

Lipson. H., and Beevers, C. A. An improved numerical method of two-dimensional Fourier synthesis for crystals. Proc. Phys. Soc. 48, 772-780 (1936). Patterson, A. L., and Tunell, G. A method for the summation of the Fourier series used in the X-ray analysis of crystal structures. Amer. Mineralogist 27. 655-679 (1942). 

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