7[4]A Short Biography of Alfred James Lotka,prepared by the National Institue of Standards and Technology.http://www.nist.gov/dads/HTML/lotkaslaw.html.
9[6]Carston,R.Informativeness,Relevance and Scalar Implicature[A].Relevance Theory:Applications and Implications[C].Ed.R.Carston & S.Uchida.Amsterdam:John Benjamins,1998.179-236.
10[7]Catriona T.and J.R.Hurford.Modelling Zipfian Distributions in Language.(paper presented at the Language Evolution and Computation Workshop/Course at the 15th European Summer School on Logic,Language and Information,Vienna,Auguast 2003.from http://www.ling.ed.ac.uk/~jim.)