links -  references :

ARTA  - linking table (synonyms) :

http://en.wikipedia.org/wiki/Levenshtein_distance

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.18.2138&rep=rep1&type=pdf

http://www.java2s.com/Open-Source/Java-Document/Net/lucene-connector/org/apache/lucene/analysis/snowball/SnowballFilter.java.htm