X-ray crystallography is a very powerful technique that provides the three-dimensional structure of a crystalline molecule or material. It is an important technique that can give a high-resolution three-dimensional structure including bond distances, angles, stereochemistry, and absolute configuration. The main disadvantages of this technique are that it requires a good single crystal sample and that the solid-state structure may not accurately represent the solution structure.
Listed below are the reference for the X-ray crystal structure for ferritin and a general reference for X-ray crystallography.
Ferritin reference: D. M. Lawson, et al., NATURE, 349, 541 (1991). "Solving the Structure of Human H Ferritin by Genetically Engineering Intermolecular Crystal Contacts."
General reference: J. P. Glusker and K. N. Trueblood, Crystal Structure Analysis, A Primer. (Oxford University Press, New York, 1985).