“A Review on Enabling Synonym Based Fined-grained Multi-keyword Search Using Hierarchical Clustering”, Int. J. Emerg. Trends Sci. Technol., vol. 3, no. 12, pp. 4866–4870, Dec. 2016, Accessed: Oct. 24, 2026. [Online]. Available: https://www.ijetst.in/index.php/ijetst/article/view/1377