Detecting multiple authorship of United States Supreme Court legal   decisions using function words
  This paper uses statistical analysis of function words used in legal judgments written by United States Supreme Court justices, to determine which justices have the most variable writing style (which may indicated greater reliance on their law clerks when writing opinions), and also the extent to which different justices' writing styles are distinguishable from each other. 
Jeffrey S. Rosenthal, Albert H. Yoon
stat.AP