Blömer, Johannes, Sascha Brauer, and Kathrin Bujna. “A Theoretical Analysis of the Fuzzy K-Means Problem.”https://doi.org/10.1109/icdm.2016.0094__In 2016 IEEE 16th International Conference on Data Mining (ICDM), 805–10. IEEE, 2016.https://doi.org/10.1109/icdm.2016.0094 .