1. 1. Reeve Lawrence H., Han Hyoil, Nagori Saya V., Yang Jonathan C., Schwimmer Tamara A., Brooks Ari D., “Concept Frequency Distribution in Biomedical Text Summarization”, ACM 15th Conference on Information and Knowledge Management (CIKM), Arlington, VA, USA,2006.
   2. Vishal Gupta and Gurpreet Singh Lehal, “A Survey of Text Summarization Extractive Techniques”, Journal of Emerging Technologies in Web Intelligence, Vol. 2, No. 3, August 2010.
   3. N.Moratanch and S.Chitrakala, "A Survey on Extractive Text Summarization", IEEE International Conference on Computer, Communication, and Signal Processing, 2017.
   4.  Rajvardhan Oak, “Extractive Techniques for Automatic Document Summarization: A Survey”. International Journal of Innovative Research in Computer and Communication Engineering, Vol. 4, Issue 3, March 2016. 
   5. J. L. Neto, A. A. Freitas, and C. A. Kaestner, "Automatic text summarization using a machine learning approach," in Advances in Artificial Intelligence. Springer, 2002, pp. 205-215.
   6. Saranyamol C S, Sindhu L, “A Survey on Automatic Text Summarization”, International Journal of Computer Science and Information Technologies, 2014,Vol. 5 Issue