It was recalled that formulations of twinning theory usually combined at least 2 different types of observation. These were measurements of the macroscopic deformation, and measurements made using X-rays. It was concluded here that there was some advantage in considering the latter separately. This was because the 2 types of data often did not relate to each other very well. Proposed improvements to twinning theory, based upon the theory of X-ray observation, were proposed.

Twinning Analyses in X-Ray Theory. J.L.Ericksen: International Journal of Solids and Structures, 2001, 38, 967-95