D. P. Agustino, I. G. Harsemadi, and I. G. B. A. Budaya, “Edutech Digital Start-Up Customer Profiling Based on RFM Data Model Using K-Means Clustering”, journalisi, vol. 4, no. 3, pp. 724–736, Sep. 2022, doi: 10.51519/journalisi.v4i3.322.