Basriati, S., Safitri, E. and Sartika, D. (2021) “Optimization of Drinking Water Distribution Costs Using Vogel’s Approximation Method (VAM) and Three Modified Methods of VAM (Case Study: Sikumbang Kampar Spring)”, Numerical: Jurnal Matematika dan Pendidikan Matematika, 5(2), pp. 103–114. doi: 10.25217/numerical.v5i2.1419.