1. 1. S. Wang and W. Shi, “Data mining and knowledge discovery,” in Springer Handbook of Geographic Information, 2012.
   2. M. Tsytsarau and T. Palpanas, “Survey on mining subjective data on the web,” Data Min. Knowl. Discov., 2012.
   3.  “Web data mining: exploring hyperlinks, contents, and usage data,” Choice Rev. Online, 2012.
   4. K. Khan, B. Baharudin, A. Khan, and A. Ullah, “Mining opinion components from unstructured reviews: A review,” Journal of King Saud University - Computer and Information Sciences. 2014.
   5. J. Serrano-Guerrero, J. A. Olivas, F. P. Romero, and E. Herrera-Viedma, “Sentiment analysis: A review and comparative analysis of web services,” Inf. Sci. (Ny)., 2015. 
   6.  S. Ghosh, S. Roy, and S. K. Bandyopadhyay, “A tutorial review on Text Mining Algorithms,” Int. J. Adv. Res. Comput. Commun. Eng., 2012.
   7. C. Romero, P. G. Espejo, A. Zafra, J. R. Romero, and S. Ventura, “Web usage mining for predicting final marks of students that use Moodle courses,” Comput. Appl. Eng. Educ., 2013.
   8. M. Nickel, K. Murphy, V. Tresp, and E. Gabrilovich, “A review of relational machine learning for knowledge graphs,” Proceedings of the IEEE. 2016. 
   9.  R. Irfan et al., “A survey on text mining in social networks,” Knowledge Engineering Review. 2015.