Sumartika Br Hutasoit, Budi Serasi Ginting and Fuzi Yustika Manik 2022. Grouping Library Book Collection Based On Old Book Borrowers With Clustering Method (Case study: STMIK Kaputama). International Journal of Health Engineering and Technology (IJHET). 1, 2 (Jul. 2022). DOI:https://doi.org/10.55227/ijhet.v1i2.36.