1. Aggarwal, C.C., Zhai, C.X.: Mining Text Data, pp. 12–14. Springer US (2012)
2. Chandrasekar, R., Srinivas, B.: Automatic induction of rules for text simplification. University of Pennsylvania Institute for Research in Cognitive Science Technical Report No. IRCS-96-30 (1996)
3. IFIP;F. Colas,2006
4. Definition of word lammatize (2014),
http://www.thefreedictionary.com/lemmatise
5. Esuli, A., Baccianella, S., Sebastiani, F.: Sentiwordnet3.0: An enhanced lexical resource for sentiment analysis and opinion mining (2010)