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   2. 2. Zaki & Meira. Data Mining and Analysis Fundamental concepts and Algorithms. 2014
   3. 3. Cluster Detection. Retrieved from tuoitre.mobi/tukhoa/k-means-clustering-example-631198.html
   4. 4. K Nearest Neighbors. Retrieved from https://machinelearningmastery.com/tutorial-to-implementk-nearest-neighbors-in-python-from-scratch/