1. Pang B, Lee L L. Opinion mining and sentiment analysis. Found Trends Inf Retr, 2008, 2: 1–135
2. Liu B. Sentiment analysis and opinion mining. Synth Lect Human Language Tech, 2012, 5: 1–167
3. Abbasi A, Chen H, Salem A. Sentiment analysis in multiple languages: feature selection for opinion classification in web forums. ACM Trans Inf Syst, 2008, 26: 1–34
4. Duric A, Song F. Feature selection for sentiment analysis based on content and syntax models. Decis Support Syst, 2012, 53: 704–711
5. Bloom K, Garg N, Argamon S. Extracting appraisal expressions. In: Proceedings of Human Language Technologies: the Annual Conference of the North American Chapter of the Association for Computational Linguistics, Rochester, 2007. 308–315