http://vims.cis.udel.edu/~mani/NLP/ Fred J. Damerau, A technique for computer detection and correction of spelling errors, Communications of the ACM, Volume 7, Issue 3 (March 1964), Pages 171 - 176 http://vims.cis.udel.edu/~mani/NLP/Damerau%20-%20Detecting%20and%20Corecting%20Spelling%20errors.pdf Karen Kukich, Technique for automatically correcting words in text, ACM Computing Surveys (CSUR), Volume 24, Issue 4 (December 1992), Pages 377 - 439 http://vims.cis.udel.edu/~mani/NLP/Kukich%20-%20Techniques%20for%20automatically%20correcting%20Words.pdf J. Grundin, Error patterns in skilled and novice transcription typing, Cognitive Aspects of Skilled Typewriting, W. E. Copper, Ed. Springer-Verlag, New York.