Using the Wigner-Ibach Surmise to Analyze Terrace-Width Distributions:   History, User's Guide, and Advances
  A history is given of the applications of the simple expression generalized from the surmise by Wigner and also by Ibach to extract the strength of the interaction between steps on a vicinal surface, via the terrace width distribution (TWD). A concise guide for use with experiments and a summary of some recent extensions are provided. 
T. L. Einstein