A Technique for Computer Detection and Correction of Spelling Errors*
The method described assumes that a word
which cannot be found in a dictionary has at most 
one error, which might be a wrong, missing or extra letter
or a single transposition.  The unidentified 
input word is compared to the dictionary again, testing
each time to see if the words match-assuming 
one of these errors occurred.  During a test run on garbled
text, correct identifications were made for 
over 95 percent of these error types.
CACM March, 1964
Damerau, F. J.
