No X-ray lens

[1]  Graeme Morrison,et al.  X-Ray Microscopy III , 1992 .

[2]  Alan G. Michette,et al.  Optical Systems for Soft X Rays , 2011, Springer US.

[3]  S. Suehiro,et al.  Refractive lens for X-ray focus , 1991, Nature.